Graphene Oxide Nanoparticle-Loaded Ginsenoside Rg3 Improves Photodynamic Therapy in Inhibiting Malignant Progression and Stemness of Osteosarcoma

Natural compounds-based nanomedicines for cancer treatment: Future directions and challenges

Several efforts have been extensively accomplished for the amelioration of the cancer treatments using different types of new drugs and less invasives therapies in comparison with the traditional therapeutic modalities, which are widely associated with numerous drawbacks, such as drug resistance, non-selectivity and high costs, restraining their clinical response. The application of natural compounds for the prevention and treatment of different cancer cells has attracted significant attention from the pharmaceuticals and scientific communities over the past decades. Although the use of nanotechnology in cancer therapy is still in the preliminary stages, the application of nanotherapeutics has demonstrated to decrease the various limitations related to the use of natural compounds, such as physical/chemical instability, poor aqueous solubility, and low bioavailability. Despite the nanotechnology has emerged as a promise to improve the bioavailability of the natural compounds, there are still limited clinical trials performed for their application with various challenges required for the pre-clinical and clinical trials, such as production at an industrial level, assurance of nanotherapeutics long-term stability, physiological barriers and safety and regulatory issues. This review highlights the most recent advances in the nanocarriers for natural compounds secreted from plants, bacteria, fungi, and marine organisms, as well as their role on cell signaling pathways for anticancer treatments. Additionally, the clinical status and the main challenges regarding the natural compounds loaded in nanocarriers for clinical applications were also discussed.

Graphene-based hybrid composites for cancer diagnostic and therapy

The application of graphene-based nanocomposites for therapeutic and diagnostic reasons has advanced considerably in recent years due to advancements in the synthesis and design of graphene-based nanocomposites, giving rise to a new field of nano-cancer diagnosis and treatment. Nano-graphene is being utilized more often in the field of cancer therapy, where it is employed in conjunction with diagnostics and treatment to address the complex clinical obstacles and problems associated with this life-threatening illness. When compared to other nanomaterials, graphene derivatives stand out due to their remarkable structural, mechanical, electrical, optical, and thermal capabilities. The high specific surface area of these materials makes them useful as carriers in controlled release systems that respond to external stimuli; these compounds include drugs and biomolecules like nucleic acid sequences (DNA and RNA). Furthermore, the presence of distinctive sheet-like nanostructures and the capacity for photothermal conversion have rendered graphene-based nanocomposites highly favorable for optical therapeutic applications, including photothermal treatment (PTT), photodynamic therapy (PDT), and theranostics. This review highlights the current state and benefits of using graphene-based nanocomposites in cancer diagnosis and therapy and discusses the obstacles and prospects of their future development. Then we focus on graphene-based nanocomposites applications in cancer treatment, including smart drug delivery systems, PTT, and PDT. Lastly, the biocompatibility of graphene-based nanocomposites is also discussed to provide a unique overview of the topic.

Research progress of nano-delivery systems for the active ingredients from traditional Chinese medicine

INTRODUCTION

Traditional Chinese medicine (TCM) has been used for thousands of years in China, characterizing with novel pharmacological mechanisms, low toxicity, and limited side effects. However, the application of TCM active ingredients is often hindered by their physical and chemical properties, including poor solubility, low bioavailability, short half-life, toxic side effects within therapeutic doses, and instability in biological environments. Consequently, an increasing number of researchers are directing their attention towards the discovery of nano-delivery systems for TCM to overcome these clinical challenges.

OBJECTIVES

This review aims to provide the latest knowledge and results concerning the studies on the nano-delivery systems for the active ingredients from TCM.

MATERIALS AND METHODS

Recent literature relating to nano-delivery systems for the active ingredients from TCM is summarized to provide a fundamental understanding of how such systems can enhance the application of phytochemicals.

RESULTS

The nano-delivery systems of six types of TCM monomers are summarized and categorized based on the skeletal structure of the natural compounds. These categories include terpenoids, flavonoids, alkaloids, quinones, polyphenols, and polysaccharides. The paper analyzes the characteristics, types, materials used, and the efficacy achieved by TCM-nano systems. Additionally, the advantages and disadvantages of nano-drug delivery systems for TCM are summarized in this paper.

CONCLUSION

Nano-delivery systems represent a promising approach to overcoming clinical obstacles stemming from the physical and chemical properties of TCM active ingredients, thereby enhancing their clinical efficacy.

Unveiling the experimental proof of the anticancer potential of ginsenoside Rg3 (Review)

Ginsenoside Rg3 (GS-Rg3), a sterol molecule isolated from ginseng, has demonstrated various immunological properties, including inhibition of cancer cell proliferation and metastasis, reversal of drug resistance and enhancement of chemotherapy sensitivity. The recent surge in attention towards GS-Rg3 can be attributed to its potential as an antitumor angiogenesis agent and as a therapeutic candidate for immunotherapy. The development of GS-Rg3 as an agent for these purposes has accelerated research on its mechanisms of action. The present review summarizes recent studies investigating the antitumor activity of GS-Rg3 and its underlying mechanisms, as well as providing essential information for future studies on GS-Rg3.

Current approaches in tissue engineering-based nanotherapeutics for osteosarcoma treatment

Osteosarcoma (OS) is a malignant bone neoplasm plagued by poor prognosis. Major treatment strategies include chemotherapy, radiotherapy, and surgery. Chemotherapy to treat OS has severe adverse effects due to systemic toxicity to healthy cells. A possible way to overcome the limitation is to utilize nanotechnology. Nanotherapeutics is an emerging approach in treating OS using nanoparticulate drug delivery systems. Surgical resection of OS leaves a critical bone defect requiring medical intervention. Recently, tissue engineered scaffolds have been reported to provide physical support to bone defects and aid multimodal treatment of OS. These scaffolds loaded with nanoparticulate delivery systems could also actively repress tumor growth and aid new bone formation. The rapid developments in nanotherapeutics and bone tissue engineering have paved the way for improved treatment efficacy for OS-related bone defects. This review focuses on current bifunctional nanomaterials-based tissue engineered (NTE) scaffolds that use novel approaches such as magnetic hyperthermia, photodynamic therapy, photothermal therapy, bioceramic and polymeric nanotherapeutics against OS. With further optimization and screening, NTE scaffolds could meet clinical applications for treating OS patients.

Graphene Oxide (GO) for the Treatment of Bone Cancer: A Systematic Review and Bibliometric Analysis

Cancer is a severe disease that, in 2022, caused more than 9.89 million deaths worldwide. One worrisome type of cancer is bone cancer, such as osteosarcoma and Ewing tumors, which occur more frequently in infants. This study shows an active interest in the use of graphene oxide and its derivatives in therapy against bone cancer. We present a systematic review analyzing the current state of the art related to the use of GO in treating osteosarcoma, through evaluating the existing literature. In this sense, studies focused on GO-based nanomaterials for potential applications against osteosarcoma were reviewed, which has revealed that there is an excellent trend toward the use of GO-based nanomaterials, based on their thermal and anti-cancer activities, for the treatment of osteosarcoma through various therapeutic approaches. However, more research is needed to develop highly efficient localized therapies. It is suggested, therefore, that photodynamic therapy, photothermal therapy, and the use of nanocarriers should be considered as non-invasive, more specific, and efficient alternatives in the treatment of osteosarcoma. These options present promising approaches to enhance the effectiveness of therapy while also seeking to reduce side effects and minimize the damage to surrounding healthy tissues. The bibliometric analysis of photothermal and photochemical treatments of graphene oxide and reduced graphene oxide from January 2004 to December 2022 extracted 948 documents with its search strategy, mainly related to research papers, review papers, and conference papers, demonstrating a high-impact field supported by the need for more selective and efficient bone cancer therapies. The central countries leading the research are the United States, Iran, Italy, Germany, China, South Korea, and Australia, with strong collaborations worldwide. At the same time, the most-cited papers were published in journals with impact factors of more than 6.0 (2021), with more than 290 citations. Additionally, the journals that published the most on the topic are high impact factor journals, according to the analysis performed, demonstrating the high impact of the research field.

Nano-Based Drug Delivery Systems: Potential Developments in the Therapy of Metastatic Osteosarcoma-A Narrative Review

Osteosarcoma, a predominant malignant bone tumor, poses significant challenges due to its high metastatic and recurrent nature. Although various therapeutic strategies are currently in use, they often inadequately target osteosarcoma metastasis. This review focuses on the potential of nanoscale drug delivery systems to bridge this clinical gap. It begins with an overview of the molecular mechanisms underlying metastatic osteosarcoma, highlighting the limitations of existing treatments. The review then transitions to an in-depth examination of nanoscale drug delivery technologies, emphasizing their potential to enhance drug bioavailability and reduce systemic toxicity. Central to this review is a discussion of recent advancements in utilizing nanotechnology for the potential intervention of metastatic osteosarcoma, with a critical analysis of several preclinical studies. This review aims to provide insights into the potential applications of nanotechnology in metastatic osteosarcoma therapy, setting the stage for future clinical breakthroughs and innovative cancer treatments.

Graphene oxide nanoarchitectures in cancer therapy: Drug and gene delivery, phototherapy, immunotherapy, and vaccine development

The latest advancements in oncology involves the creation of multifunctional nanostructures. The integration of nanoparticles into the realm of cancer therapy has brought about a transformative shift, revolutionizing the approach to addressing existing challenges and limitations in tumor elimination. This is particularly crucial in combating the emergence of resistance, which has significantly undermined the effectiveness of treatments like chemotherapy and radiotherapy. GO stands as a carbon-derived nanoparticle that is increasingly finding utility across diverse domains, notably in the realm of biomedicine. The utilization of GO nanostructures holds promise in the arena of oncology, enabling precise transportation of drugs and genetic material to targeted sites. GO nanomaterials offer the opportunity to enhance the pharmacokinetic behavior and bioavailability of drugs, with documented instances of these nanocarriers elevating drug accumulation at the tumor location. The GO nanostructures encapsulate genes, shielding them from degradation and facilitating their uptake within cancer cells, thereby promoting efficient gene silencing. The capability of GO to facilitate phototherapy has led to notable advancements in reducing tumor progression. By PDT and PTT combination, GO nanomaterials hold the capacity to diminish tumorigenesis. GO nanomaterials have the potential to trigger both cellular and innate immunity, making them promising contenders for vaccine development. Additionally, types of GO nanoparticles that respond to specific stimuli have been applied in cancer eradication, as well as for the purpose of cancer detection and biomarker diagnosis. Endocytosis serves as the mechanism through which GO nanomaterials are internalized. Given these advantages, the utilization of GO nanomaterials for tumor elimination comes highly recommended.

Eradicating the tumor "seeds": nanomedicines-based therapies against cancer stem cells

OBJECTIVES

Cancer stem cells (CSCs), a small subpopulation of cells with high tumorigenesis and strong intrinsic drug resistance, exhibit self-renewal and differentiation abilities. CSCs play a crucial role in tumor progression, drug resistance, recurrence and metastasis,and conventional therapy is not enough to eradicate them. Therefore, developing novel therapies targeting CSCs to increase drug sensitivity and preventing relapse is essential. The objective of this review is to present nanotherapies that target and eradicate the tumor "seeds".

EVIDENCE ACQUISITION

Evidence was collected and sorted from the literature ranging from 2000 to 2022, using appropriate keywords and key phrases as search terms within scientific databases such as Web of Science, PubMed and Google Scholar.

RESULTS

Nanoparticle drug delivery systems have been successfully applied to gain longer circulation time, more precise targeting capability and better stability during cancer treatment. Nanotechnology-based strategies that have been used to target CSCs, include (1) encapsulating small molecular drugs and genes by nanotechnology, (2) targeting CSC signaling pathways, (3) utilizing nanocarriers targeting for specific markers of CSCs, (4) improving photothermal/ photodynamic therapy (PTT/PDT), 5)targeting the metabolism of CSCs and 6) enhancing nanomedicine-aided immunotherapy.

CONCLUSION

This review summarizes the biological hallmarks and markers of CSCs, and the nanotechnology-based therapies to kill them. Nanoparticle drug delivery systems are appropriate means for delivering drugs to tumors through enhanced permeability and retention (EPR) effect. Furthermore, surface modification with special ligands or antibodies improves the recognition and uptake of tumor cells or CSCs. It is expected that this review can offer insights into features of CSCs and the exploration of targeting nanodrug delivery systems.

Selenium-incorporated mesoporous silica nanoparticles for osteosarcoma therapy

Selenium (Se) compounds are promising chemotherapeutics due to their ability to inhibit cancer cell activity via the generation of reactive oxygen species (ROS). However, to circumvent adverse effects on bone healthy cells, new methods are needed to allow intracellular Se delivery. Mesoporous silica nanoparticles (MSNs) are promising carriers for therapeutic ion delivery due to their biocompability, rapid uptake via endocytosis, and ability to efficiently incorporate ions within their tunable structure. With the aim of selectively inhibiting cancer cells, here we developed three types of MSNs and investigated their ability to deliver Se. Specifically, MSNs containing SeO32- loaded on the surface and in the pores (MSN-SeL), SeO32- doped in the silica matrix (Se-MSNs) and Se nanoparticles (SeNP) coated with mesoporous silica (SeNP-MSNs), were successfully synthesized. All synthesized nanoparticles were stable in neutral conditions but showed rapid Se release in the presence of glutathione (GSH) and nicotinamide adenine dinucleotide phosphate (NADPH). Furthermore, all nanoparticles were cytotoxic towards SaoS-2 cells and showed significantly lower toxicity towards healthy osteoblasts, where Se doped MSNs showed lowest toxicity towards osteoblasts. We further show that the nanoparticles could induce ROS and cell apoptosis. Here we demonstrate MSNs as promising Se delivery carriers for osteosarcoma (OS) therapy.

Nanobiotechnological approaches in osteosarcoma therapy: Versatile (nano)platforms for theranostic applications

Constructive achievements in the field of nanobiotechnology and their translation into clinical course have led to increasing attention towards evaluation of their use for treatment of diseases, especially cancer. Osteosarcoma (OS) is one of the primary bone malignancies that affects both males and females in childhood and adolescence. Like other types of cancers, genetic and epigenetic mutations account for OS progression and several conventional therapies including chemotherapy and surgery are employed. However, survival rate of OS patients remains low and new therapies in this field are limited. The purpose of the current review is to provide a summary of nanostructures used in OS treatment. Drug and gene delivery by nanoplatforms have resulted in an accumulation of therapeutic agents for tumor cell suppression. Furthermore, co-delivery of genes and drugs by nanostructures are utilized in OS suppression to boost immunotherapy. Since tumor cells have distinct features such as acidic pH, stimuli-responsive nanoparticles have been developed to appropriately target OS. Besides, nanoplatforms can be used for biosensing and providing phototherapy to suppress OS. Furthermore, surface modification of nanoparticles with ligands can increase their specificity and selectivity towards OS cells. Clinical translation of current findings suggests that nanoplatforms have been effective in retarding tumor growth and improving survival of OS patients.

Graphene family in cancer therapy: recent progress in cancer gene/drug delivery applications

In the past few years, the development in the construction and architecture of graphene based nanocomplexes has dramatically accelerated the use of nano-graphene for therapeutic and diagnostic purposes, fostering a new area of nano-cancer therapy. To be specific, nano-graphene is increasingly used in cancer therapy, where diagnosis and treatment are coupled to deal with the clinical difficulties and challenges of this lethal disease. As a distinct family of nanomaterials, graphene derivatives exhibit outstanding structural, mechanical, electrical, optical, and thermal capabilities. Concurrently, they can transport a wide variety of synthetic agents, including medicines and biomolecules, such as nucleic acid sequences (DNA and RNA). Herewith, we first provide an overview of the most effective functionalizing agents for graphene derivatives and afterward discuss the significant improvements in the gene and drug delivery composites based on graphene.

The safety and efficiency of photodynamic therapy for the treatment of osteosarcoma: A systematic review of in vitro experiment and animal model reports

BACKGROUND

Osteosarcoma (OS) is an aggressive malignant bone tumour with high mortality. A poor prognosis is noted in patients with distal metastases or multidrug resistance. As an emerging antitumor strategy, photodynamic therapy (PDT) mediated by visible and near infrared light has attracted intensive attention given its target selectivity, remote controllability, minimal or non-invasive features. However, PDT also has obvious limitations. Specifically, due to the limited penetration of light, it is mainly used in the clinical treatment of superficial malignant tumours, such as musculoskeletal sarcomas and melanoma, but it has not been applied to the clinical treatment of deep malignant bone tumours except for a very small number of experiments on deep canine OS models.

MATERIALS AND METHODS

We searched for studies that focused on the effectiveness and safety of PDT for OS based on in vitro experiments and animal models in the last decade. A systematic search was conducted using electronic databases, including PubMed, ClinicalTrials.gov, and the Cochrane Library.

INCLUSION CRITERIA

(1) original research articles about PDT for OS; (2) articles in English; (3) in vitro or animal model research; and (4) detailed information, including cell name, fluence, irradiation wavelength, time of incubation with PS, duration between PS treatment and irradiation, and duration between irradiation and viability assays.

EXCLUSION CRITERIA

(1) study was a review/systemic review article, patent, letter, or conference abstract/paper; (2) articles were not published in English; (3) studies containing overlapping or insufficient data.

RESULTS

We identified 201 publications, and 44 articles met the inclusion criteria and were included in the synthesis. Unfortunately, there are no relevant clinical reports of the use of PDT in the treatment of human OS. In these studies, 8 studies only employed in vivo experiments to evaluate the efficiency of PDT in an OS animal model, 19 studies exclusively performed in vitro viability assays of cells treated with PDT under different conditions, and 17 studies included in vitro cell experiments and in vivo animal OS models to evaluate the effect of PDT on OS in vivo and in vitro. All studies have shown that PDT is cytotoxic to OS cells or can inhibit the growth of OS in heterologous or homologous animal OS models but exhibits minimal cytotoxicity at a certain range of dosages.

CONCLUSION

Based on this systematic review, PDT can eradicate OS cells in cell culture and there is some evidence for efficacy in animal models. However, the ability for PDT to control human OS is unclear, the animal and human reports do not show evidence of human OS control, they just do show feasibility. The major issues concerning the potential for treatment of osteosarcoma with PDT are that adequate light should be transmitted to tumor loci and if the disease is caught before metastasis and irradiation of tumor sites is feasible, curative potential is there. Otherwise, PDT may be mainly palliative. To determine whether PDT can safely and efficiently be used in the clinical treatment of OS, many preclinical orthotopic animal OS models and OS models of multiple systemic metastases must be performed and interstitial PDT or intraoperative PDT may be a good and potential candidate for human OS treatment. If these problems can be well solved, PDT may be a potentially effective strategy for the treatment of OS patients.

Application and prospect of ROS-related nanomaterials for orthopaedic related diseases treatment

The importance of reactive oxygen species (ROS) in the occurrence and development of orthopaedic related diseases is becoming increasingly prominent. ROS regulation has become a new method to treat orthopaedic related diseases. In recent years, the application of nanomaterials has become a new hope for precision and efficient treatment. However, there is a lack of reviews on ROS-regulated nanomaterials for orthopaedic related diseases. Based on the key significance of nanomaterials for the treatment of orthopaedic related diseases, we searched the latest related studies and reviewed the nanomaterials that regulate ROS in the treatment of orthopaedic related diseases. According to the function of nanomaterials, we describe the scavenging of ROS related nanomaterials and the generation of ROS related nanomaterials. In this review, we closely integrated nanomaterials with the treatment of orthopaedic related diseases such as arthritis, osteoporosis, wound infection and osteosarcoma, etc., and highlighted the advantages and disadvantages of existing nanomaterials. We also looked forward to the design of ROS-regulated nanomaterials for the treatment of orthopaedic related diseases in the future.

Natural Products-Based Nanoformulations: A New Approach Targeting CSCs to Cancer Therapy

Cancer stem cells (CSCs) lead to the occurrence and progression of cancer due to their strong tumorigenic, self-renewal, and multidirectional differentiation abilities. Existing cancer treatment methods cannot effectively kill or inhibit CSCs but instead enrich them and produce stronger proliferation, invasion, and metastasis capabilities, resulting in cancer recurrence and treatment resistance, which has become a difficult problem in clinical treatment. Therefore, targeting CSCs may be the most promising approach for comprehensive cancer therapy in the future. A variety of natural products (NP) have significant antitumor effects and have been identified to target and inhibit CSCs. However, pharmacokinetic defects and off-target effects have greatly hindered their clinical translation. NP-based nanoformulations (NPNs) have tremendous potential to overcome the disadvantages of NP against CSCs through site-specific delivery and by improving their pharmacokinetic parameters. In this review, we summarize the recent progress of NPNs targeting CSCs in cancer therapy, looking forward to transforming preclinical research results into clinical applications and bringing new prospects for cancer treatment.

Pharmacological properties, molecular mechanisms and therapeutic potential of ginsenoside Rg3 as an antioxidant and anti-inflammatory agent

Inflammation and oxidative stress lead to various acute or chronic diseases, including pneumonia, liver and kidney injury, cardiovascular and cerebrovascular diseases, metabolic diseases, and cancer. Ginseng is a well-known and widely used ethnic medicine in Asian countries, and ginsenoside Rg3 is a saponin isolated from Panax ginseng C. A. Meyer, Panax notoginseng, or Panax quinquefolius L. This compound has a wide range of pharmacological properties, including antioxidant and anti-inflammatory activities, which have been evaluated in disease models of inflammation and oxidative stress. Rg3 can attenuate lung inflammation, prevent liver and kidney function damage, mitigate neuroinflammation, prevent cerebral and myocardial ischemia–reperfusion injury, and improve hypertension and diabetes symptoms. The multitarget, multipathway mechanisms of action of Rg3 have been gradually deciphered. This review summarizes the existing knowledge on the anti-inflammatory and antioxidant effects and underlying molecular mechanisms of ginsenoside Rg3, suggesting that ginsenoside Rg3 may be a promising candidate drug for the treatment of diseases with inflammatory and oxidative stress conditions.

Development of Graphene-Based Materials in Bone Tissue Engineaering

Bone regeneration-related graphene-based materials (bGBMs) are increasingly attracting attention in tissue engineering due to their special physical and chemical properties. The purpose of this review is to quantitatively analyze mass academic literature in the field of bGBMs through scientometrics software CiteSpace, to demonstrate the rules and trends of bGBMs, thus to analyze and summarize the mechanisms behind the rules, and to provide clues for future research. First, the research status, hotspots, and frontiers of bGBMs are analyzed in an intuitively and vividly visualized way. Next, the extracted important subjects such as fabrication techniques, cytotoxicity, biodegradability, and osteoinductivity of bGBMs are presented, and the different mechanisms, in turn, are also discussed. Finally, photothermal therapy, which is considered an emerging area of application of bGBMs, is also presented. Based on this approach, this work finds that different studies report differing opinions on the biological properties of bGBMS due to the lack of consistency of GBMs preparation. Therefore, it is necessary to establish more standards in fabrication, characterization, and testing for bGBMs to further promote scientific progress and clinical translation.

Application of Nanoparticles in Drug Delivery for the Treatment of Osteosarcoma: Focusing on the Liposomes

Osteosarcoma (OS) is one of the most common primary bone malignancies in children and adolescents. The toxicity to healthy tissues from conventional therapeutic strategies, including chemotherapy and radiotherapy, and drug resistance, severely affect OS patients' quality of life and cancer-specific outcomes. Many efforts have been made to develop various nanomaterial-based drug delivery systems with specific properties to overcome these limitations. Among the developed nanocarriers, liposomes are the most successful and promising candidates for providing targeted tumor therapy and enhancing the safety and therapeutic effect of encapsulated agents. Liposomes have low immunogenicity, high biocompatibility, prolonged half-life, active group protection, cell-like membrane structure, safety, and effectiveness. This review will discuss various nanomaterial-based carriers in cancer therapy and then the characteristics and design of liposomes with a particular focus on the targeting feature. We will also summarize the recent advances in the liposomal drug delivery system for OS treatment in preclinical and clinical studies.

Ginsenoside Rg3 inhibits osteosarcoma progression by reducing circ_0003074 expression in a miR-516b-5p/KPNA4-dependent manner

Background

Previous data have suggested that ginsenoside Rg3 (Rg3), isolated from the roots of Panax ginseng, plays a repressing role in multiple cancers, including osteosarcoma (OS). However, there is no any literature available about the role of circular RNA (circRNA) in Rg3-mediated OS development. The study aimed to explore the function of circ_0003074 in the anti-cancer effects of Rg3 on OS.

Methods

RNA expression of circ_0003074, miR-516b-5p and karyopherin subunit alpha 4 (KPNA4) was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Protein expression was evaluated by Western blotting or immunohistochemistry assay. Cell viability, proliferation, apoptosis, migration and invasion were investigated by cell counting kit-8, 5-ethynyl-29-deoxyuridine (EdU), flow cytometry analysis, wound-healing and transwell invasion assays, respectively. Dual-luciferase reporter and/or RNA immunoprecipitation assay was performed to confirm the interplay between miR-516b-5p and circ_0003074 or KPNA4. Xenograft mouse model assay was conducted to reveal the effect of Rg3 treatment on tumor formation.

Results

Circ_0003074 and KPNA4 expression was significantly upregulated, while miR-516b-5p was downregulated in OS tissues and cells compared with controls. Rg3 treatment dramatically decreased circ_0003074 expression in OS cells. Rg3 treatment led to decreased cell proliferation, migration and invasion but increased cell apoptosis, which was attenuated after circ_0003074 overexpression. Besides, miR-516b-5p was a target miRNA of circ_0003074 and partially restored circ_0003074-mediated action under Rg3 treatment. Decreasing miR-516b-5p expression also promoted Rg3-treated OS cell malignancy through KPNA4, which was identified as a target mRNA of miR-516b-5p. Besides, circ_0003074 induced KPNA4 production owing to the decrease of miR-516b-5p expression. Furthermore, Rg3 treatment inhibited tumor formation by regulating circ_0003074 in vivo.

Conclusion

Rg3 inhibited OS progression through circ_0003074/miR-516b-5p/KPNA4 axis, showing the potential of Rg3 as a therapeutic agent for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-021-02868-7.

Circ_0003074 expression was upregulated in OS tissues and cells.

Rg3 treatment significantly decreased circ_0003074 expression in OS cells.

Circ_0003074 overexpression rescued Rg3-induced inhibition in OS progression.

Circ_0003074 induced KPNA4 production through miR-516b-5p under Rg3 treatment.

Targeting Cancer Stem Cells by Dietary Agents: An Important Therapeutic Strategy against Human Malignancies

As a multifactorial disease, treatment of cancer depends on understanding unique mechanisms involved in its progression. The cancer stem cells (CSCs) are responsible for tumor stemness and by enhancing colony formation, proliferation as well as metastasis, and these cells can also mediate resistance to therapy. Furthermore, the presence of CSCs leads to cancer recurrence and therefore their complete eradication can have immense therapeutic benefits. The present review focuses on targeting CSCs by natural products in cancer therapy. The growth and colony formation capacities of CSCs have been reported can be attenuated by the dietary agents. These compounds can induce apoptosis in CSCs and reduce tumor migration and invasion via EMT inhibition. A variety of molecular pathways including STAT3, Wnt/β-catenin, Sonic Hedgehog, Gli1 and NF-κB undergo down-regulation by dietary agents in suppressing CSC features. Upon exposure to natural agents, a significant decrease occurs in levels of CSC markers including CD44, CD133, ALDH1, Oct4 and Nanog to impair cancer stemness. Furthermore, CSC suppression by dietary agents can enhance sensitivity of tumors to chemotherapy and radiotherapy. In addition to in vitro studies, as well as experiments on the different preclinical models have shown capacity of natural products in suppressing cancer stemness. Furthermore, use of nanostructures for improving therapeutic impact of dietary agents is recommended to rapidly translate preclinical findings for clinical use.

Progress of Phototherapy Applications in the Treatment of Bone Cancer

Bone cancer including primary bone cancer and metastatic bone cancer, remains a challenge claiming millions of lives and affecting the life quality of survivors. Conventional treatments of bone cancer include wide surgical resection, radiotherapy, and chemotherapy. However, some bone cancer cells may remain or recur in the local area after resection, some are highly resistant to chemotherapy, and some are insensitive to radiotherapy. Phototherapy (PT) including photodynamic therapy (PDT) and photothermal therapy (PTT), is a clinically approved, minimally invasive, and highly selective treatment, and has been widely reported for cancer therapy. Under the irradiation of light of a specific wavelength, the photosensitizer (PS) in PDT can cause the increase of intracellular ROS and the photothermal agent (PTA) in PTT can induce photothermal conversion, leading to the tumoricidal effects. In this review, the progress of PT applications in the treatment of bone cancer has been outlined and summarized, and some envisioned challenges and future perspectives have been mentioned. This review provides the current state of the art regarding PDT and PTT in bone cancer and inspiration for future studies on PT.