Triggering of Apoptosis in Osteosarcoma 143B Cell Line by Carbon Quantum Dots via the Mitochondrial Apoptotic Signal Pathway

Advanced nanoscale drug delivery systems for bone cancer therapy

Bone tumors are relatively rare, which are complex cancers and mostly involve the long bones and pelvis. Bone cancer is mainly categorized into osteosarcoma (OS), chondrosarcoma, and Ewing sarcoma. Of these, OS is the most intimidating cancer of the bone tissue, which is mostly found in the log bones in young children and older adults. Conspicuously, the current chemotherapy modalities used for the treatment of OS often fail mainly due to (i) the non-specific detrimental effects on normal healthy cells/tissues, (ii) the possible emergence of drug resistance mechanisms by cancer cells, and (iii) difficulty in the efficient delivery of anticancer drugs to the target cells. To impose the maximal therapeutic impacts on cancerous cells, it is of paramount necessity to specifically deliver chemotherapeutic agents to the tumor site and target the diseased cells using advanced nanoscale multifunctional drug delivery systems (DDSs) developed using organic and inorganic nanosystems. In this review, we provide deep insights into the development of various DDSs applied in targeting and eradicating OS. We elaborate on different DDSs developed using biomaterials, including chitosan, collagen, poly(lactic acid), poly(lactic-co-glycolic acid), polycaprolactone, poly(ethylene glycol), polyvinyl alcohol, polyethyleneimine, quantum dots, polypeptide, lipid NPs, and exosomes. We also discuss DDSs established using inorganic nanoscale materials such as magnetic NPs, gold, zinc, titanium NPs, ceramic materials, silica, silver NPs, and platinum NPs. We further highlight anticancer drugs' role in bone cancer therapy and the biocompatibility of nanocarriers for OS treatment.

Assessment of the therapeutic potential of probiotics against carbon quantum dots-induced neurotoxicity in common carp (Cyprinus carpio)

Carbon quantum dots (CQDs) have received increasing attention in recent years for their potential toxicity. However, little is known about their neurobehavioral toxicity. This study aimed to investigate the potential mechanisms by which probiotics reduce CQDs neurotoxicity from a brain-gut axis perspective by exposing carp to CQDs and/or probiotics for five weeks. The results showed that CQDs accumulation in the brain reduces the expression of blood-brain-barrier (BBB) related genes in carp, leading to brain damage. In addition, CQDs impaired motor behavior and inhibited acetylcholinesterase activity. These abnormalities were alleviated by probiotic supplementation. Microbiomic analysis showed that probiotics improved the imbalance of intestinal flora caused by CQDs and increased the abundance of Firmicutes. Serum metabolomic analysis showed that probiotic supplementation restored the abnormal metabolic levels associated with neurological, inflammatory, and apoptotic cell death caused by CQDs. Overall, probiotic supplementation improved the CQDs-induced changes in brain damage, gut microbiology, and systemic metabolism. These results suggests that CQDs may cause neurotoxicity via the brain-gut microbial axis.

Nanosized drug delivery strategies in osteosarcoma chemotherapy

Despite recent developments worldwide in the therapeutic care of osteosarcoma (OS), the ongoing challenges in overcoming limitations and side effects of chemotherapy drugs warrant new strategies to improve overall patient survival. Spurred by rapid progress in biomedicine, nanobiotechnology, and materials chemistry, chemotherapeutic drug delivery in treatment of OS has become possible in recent years. Here, we review recent advances in the design of drug delivery system, especially for chemotherapeutic drugs in OS, and discuss the relative merits in trials along with future therapeutic options. These advances may pave the way for novel therapies requisite for patients with OS.

In vitro and in vivo toxicological evaluation of carbon quantum dots originating from Spinacia oleracea

Food-derived carbon quantum dots (CQDs) can relatively easily be synthesized and chemically manipulated for a broad spectrum of biomedical applications. However, their toxicity may hinder their actual use. Here, Spinacia oleracea-derived CQDs i.e., CQD-1 and CQD-2, were synthesized by means of different shredding methods and followed by a microwave-assisted hydrothermal approach. Subsequently, these CQDs were analyzed in vitro and in an in vivo mice model to test their biocompatibility and potential use as bioimaging agents and for activation of osteogenic differentiation. When comparing CQD-1 and CQD-2, it was found that CQD-1 exhibited 7.6 times higher photoluminescent (PL) emission intensity around 411 nm compared to CQD-2. Besides, it was found that the size distribution of CQD-1 was 2.05 ± 0.08 nm, compared with 2.14 ± 0.04 nm for CQD-2. Upon exposure to human bone marrow-derived mesenchymal stem cells (hBMSCs) in vitro, CQD-1 was endocytosed into the cytoplasm and significantly increased the differentiation of hBMSCs up to 10 μg mL^-1 after 7 and 14 days. Apparently, the presence of relatively low doses of CQD-1 showed virtually no toxic or histological effects in the major organs in vivo. In contrast, high doses of CQD-1 (1 mg mL^-1) caused cell death in vitro ranging from 35% on day 1 to 80% on day 3 post-exposure, and activated the apoptotic machinery and increased lymphocyte aggregates in the liver tissue. In conclusion, S. oleracea-derived CQDs have the potential for biomedical applications in bioimaging and activation of stem cells osteogenic differentiation. Therefore, it is postulated that CQD-1 from S. oleracea remains potential prospective material at appropriate doses and specifications.

Direct preparation of solid carbon dots by pyrolysis of collagen waste and their applications in fluorescent sensing and imaging

The fluorescent carbon dots (CDs) have found their extensive applications in sensing, bioimaging, and photoelectronic devices. In general terms, the synthesis of CDs is straight-forward, though their subsequent purification can be laborious. Therefore, there is a need for easier ways to generate solid CDs with a high conversion yield. Herein, we used collagen waste as a carbon source in producing solid CDs through a calcination procedure without additional chemical decomposition treatment of the raw material. Considering a mass of acid has destroyed the original protein macromolecules into the assembled structure with amino acids and peptide chains in the commercial extraction procedure of collagen product. The residual tissues were assembled with weak intermolecular interactions, which would easily undergo dehydration, polymerization, and carbonization during the heat treatment to produce solid CDs directly. The calcination parameters were surveyed to give the highest conversion yield at 78%, which occurred at 300°C for 2 h. N and S atomic doping CDs (N-CDs and S-CDs) were synthesized at a similar process except for immersion of the collagen waste in sulfuric acid or nitric acid in advance. Further experiments suggested the prepared CDs can serve as an excellent sensor platform for Fe³⁺ in an acid medium with high anti-interference. The cytotoxicity assays confirmed the biosafety and biocompatibility of the CDs, suggesting potential applications in bioimaging. This work provides a new avenue for preparing solid CDs with high conversion yield.

Cationic Carbon Nanoparticles Induce Inflammasome-Dependent Pyroptosis in Macrophages via Lysosomal Dysfunction

Carbon nanomaterials, including carbon dots (CDs), form a growing family of engineered nanoparticles (NPs) with widespread applications. As the rapid expansion of nanotechnologies raises safety concerns, interaction of NPs with the immune system is receiving a lot of attention. Recent studies have reported that engineered NPs may induce macrophage death by pyroptosis. Therefore, this study investigated whether cationic CDs induce pyroptosis in human macrophages and assessed the role of inflammasome and lysosome in this process. Cationic CDs were synthetized by microwave-assisted pyrolysis of citric acid and high molecular weight branched polyethyleneimine. The NPs evoked a dose-dependent viability loss in THP-1-derived macrophages. A cell leakage, an increase in IL-1β secretion and an activation of caspase-1 were also observed in response to the NPs. Inhibition of caspase-1 decreased CD-induced cell leakage and IL-1β secretion, while restoring cell viability. Besides, CDs triggered swelling and loss of integrity of lysosome, and inhibition of the lysosomal enzyme cathepsin B decreased CD-induced IL-1β secretion. Thus, our data provide evidence that cationic CDs induce inflammasome-dependent pyroptosis in macrophages via lysosomal dysfunction.

Schisandrin B suppresses osteosarcoma lung metastasis in vivo by inhibiting the activation of the Wnt/β‑catenin and PI3K/Akt signaling pathways

Osteosarcoma (OS) is the most common malignant bone tumor worldwide and is associated with a poor prognosis, often being accompanied by lung metastasis at an early stage. At present, there are several side-effects associated with the OS clinical treatment of OS, with the treatment effects often being unsatisfactory. Thus, there is an urgent need for the development of safe and effective novel drugs for the treatment of OS. Schisandrin B (Sch B) has been previously demonstrated to exhibit antitumor properties. The present study was focused on the effects of Sch B on OS cells (143B, MG63, Saos2 and U2OS) in vitro and in vivo, and also on its possible antitumor mechanisms. In cell experiments, it was revealed that Sch B inhibited OS cell proliferation, migration and invasion, and increased OS cell apoptosis. As regards its biosafety, no notable effects of Sch B on the vitality of normal cells were observed. Mechanistically, it was demonstrated that Sch B blocked OS cell proliferation in the G₁ phase. Subsequently, by using established animal models, it was revealed that Sch B significantly inhibited OS growth and lung metastasis in vivo. In summary, the results of the present study revealed that Sch B inhibited OS cell proliferation, migration and invasion, and promoted apoptosis via the inhibition of the Wnt/β-catenin and PI3K/Akt signaling pathways, without causing any noticeable toxic effects on healthy cells at the therapeutic concentrations used. These findings suggest that Sch B has potential for use as a novel agent for the clinical treatment of OS.