Unraveling the roles of miRNAs in regulating epithelial-to-mesenchymal transition (EMT) in osteosarcoma

Icariside II inhibits Epithelial-Mesenchymal transition in metastatic osteosarcoma by antagonizing the miR-194/215 cluster via PGK1

Osteosarcoma, the most prevalent malignant bone tumor in adolescents, is characterized by its aggressiveness and tendency to metastasize. Despite the advancements in treatment that have improved survival rates for localized cases, metastatic osteosarcoma remains challenging to treat due to the limited efficacy of current therapies and the severe side effects of chemotherapy. Epithelial-mesenchymal transition (EMT) is a key factor in osteosarcoma metastasis, and the miR-194/215 cluster, which is upregulated in osteosarcoma, promotes this process. This study sought to investigate natural compounds that could counteract the miR-194/215 cluster's effects and inhibit osteosarcoma metastasis. By analyzing miRNA databases and clinical data, a signature gene set for the miR-194/215 cluster was established, and the LINCS database was screened to find natural compounds with antagonistic effects. Icariside II, an active component of Epimedium, was identified as a potential inhibitor and was shown to reduce the migration and invasion of osteosarcoma cells in vitro and lung metastasis in vivo. The study utilized various techniques, including Gene Set Enrichment Analysis (GSEA), Drug Affinity Responsive Target Stability (DARTS), Cellular Thermal Shift Assay (CETSA), molecular docking, and enzyme activity assays, to identify phosphoglycerate kinase 1 (PGK1) as the target protein of Icariside II. It was found that Icariside II competitively inhibits PGK1 by binding to its ADP binding pocket, reducing its activity and thus antagonizing the miR-194/215 cluster's promotion of EMT in metastatic osteosarcoma. The results suggest that Icariside II could be a promising therapeutic agent for metastatic osteosarcoma, providing new targets and strategies for clinical treatment.

RBM15-mediated the m6A modification of MAT2A promotes osteosarcoma cell proliferation, metastasis and suppresses ferroptosis

Methionine adenosyltransferase 2 A (MAT2A) has been found to mediate osteosarcoma (OS) progression. Therefore, more roles and mechanisms of MAT2A in the development of OS deserve further exploration. The mRNA and protein levels of MAT2A and RNA binding motif protein 15 (RBM15) were tested by quantitative real-time PCR and western blot (WB). Cell proliferation and metastasis were examined using EdU assay and transwell assay. The protein levels of metastasis-related markers and ferroptosis-related marker were measured by WB. Cell ferroptosis was assessed via testing GSH, ROS, and Fe2+ levels. Mice xenograft model was constructed to explore the roles of MAT2A and RBM15 in vivo. RBM15 and MAT2A interaction was assessed by MeRIP assay and dual-luciferase reporter assay. High expression of MAT2A was observed in OS tumor tissues and cells. MAT2A knockdown reduced OS cell proliferation, migration, invasion and enhanced ferroptosis. Silencing of MAT2A inhibited OS tumor growth in vivo. RBM15 was upregulated in OS tumor tissues and cells, which could promote MAT2A expression by N6-methyladenosine (m6A) modification. Downregulation of RBM15 repressed OS cell behaviors and tumorigenesis by decreasing MAT2A expression. In conclusion, MAT2A, regulated by RBM15-mediated m6A modification, accelerated OS malignant progression by increasing cell proliferation, metastasis and decreasing ferroptosis.

Synergistic HDAC4/8 Inhibition Sensitizes Osteosarcoma to Doxorubicin via pAKT/RUNX2 Pathway Modulation

Osteosarcoma is a highly aggressive bone malignancy, particularly challenging in metastatic cases, with a 5-year survival rate remaining under 30%. Although doxorubicin (doxo) is a standard first-line chemotherapeutic agent, its clinical utility is often hindered by the development of drug resistance and associated systemic toxicity. Emerging evidence highlights the role of epigenetic alterations, particularly those involving histone deacetylases (HDACs), in promoting chemoresistance. In this context, the present study aimed to evaluate the therapeutic potential of combining doxo with the selective HDAC inhibitors, tasquinimod (Tas, targeting HDAC4) and PCI-34051 (PCI, targeting HDAC8), in SJSA-1 osteosarcoma cells. Utilizing both 2D and 3D in vitro models, the combination treatment (referred to as the T4 group) significantly reduced cell viability by 57.69% in 2D cultures and decreased spheroid volume by 35.19% in 3D models. The apoptotic response was markedly enhanced, with late apoptosis reaching 64.59% and necrosis at 32.07%, both surpassing the effects observed with doxo alone. Furthermore, wound healing assays demonstrated a 37.74% inhibition of migration, accompanied by a decreased expression of the matrix metalloproteinases MMP9 and MMP13. Mechanistically, the combination therapy led to the downregulation of protein kinase B (pAKT) and RUNX2, along with upregulation of apoptotic markers, including caspase 8, caspase 3, and cleaved caspase 3, indicating a disruption of key survival pathways. These findings suggest that dual HDAC inhibition with Tas and PCI can potentiate doxo efficacy by enhancing apoptosis, inhibiting proliferation, and reducing metastatic potential, thus offering a promising strategy to overcome chemoresistance in osteosarcoma. Further preclinical and clinical studies are required to validate these therapeutic benefits.

The Role of Epithelial-Mesenchymal Transition in Osteosarcoma Progression: From Biology to Therapy

Osteosarcoma (OS) is the most common primary malignant bone tumor, predominantly affecting children, adolescents, and young adults. Epithelial-mesenchymal transition (EMT), a process in which epithelial cells lose their cell-cell adhesion and gain migratory and invasive properties, has been extensively studied in various carcinomas. However, its role in mesenchymal tumors like osteosarcoma remains less explored. EMT is increasingly recognized as a key factor in the progression of osteosarcoma, contributing to tumor invasion, metastasis, and resistance to chemotherapy. This narrative review aims to provide a comprehensive overview of the molecular mechanisms driving EMT in osteosarcoma, highlighting the involvement of signaling pathways such as TGF-β, transcription factors like Snail, Twist, and Zeb, and the role of microRNAs in modulating EMT. Furthermore, we discuss how EMT correlates with poor prognosis and therapy resistance in osteosarcoma patients, emphasizing the potential of targeting EMT for therapeutic intervention. Recent advancements in understanding EMT in osteosarcoma have opened new avenues for treatment, including EMT inhibitors and combination therapies aimed at overcoming drug resistance. By integrating biological insights with clinical implications, this review underscores the importance of EMT as a critical process in osteosarcoma progression and its potential as a therapeutic target.

Wnt/β-catenin signaling pathway: an attractive potential therapeutic target in osteosarcoma

Osteosarcoma (OS) is the most common bone malignancy in children and adolescents, and although current neoadjuvant chemotherapy has shown efficacy against OS, the long-term survival rate for patients with OS remains low, highlighting the need to find more effective treatments. In cancer cells, abnormal activation of signaling pathways can widely affect cell activity from growth and proliferation to apoptosis, invasion and metastasis. Wnt/β-catenin is a complex and unique signaling pathway that is considered to be one of the most important carcinogenic pathways in human cancer. Research have confirmed that the Wnt/β-catenin signaling pathway is an important driving factor for the occurrence and development of osteosarcoma, and abnormal activation of this pathway can promote the pathological processes of cell proliferation, invasion, migration, tumor angiogenesis and chemical resistance of osteosarcoma. However, inhibition of Wnt/β-catenin signaling pathway can effectively inhibit or reverse the above pathological processes. Therefore, manipulating the expression or function of the Wnt/β-catenin pathway may be a potential targeted pathway for the treatment of OS. In this review, we describe the characteristics of the Wnt/β-catenin signaling pathway and summarize the role and mechanism of this pathway in OS. This paper discusses the therapeutic significance of inhibiting or targeting Wnt/β-catenin pathway in OS and the shortcomings of current studies on this pathway in OS and the problems to be solved. This review helps us to understand the role of Wnt/β-catenin on OS, and provides a theoretical basis and new ideas for targeting Wnt/β-catenin pathway as a therapeutic target for OS.

The role of lncRNA and miRNA on the effects of occurrence and development of osteosarcoma

Osteosarcoma is a common primary malignant bone tumor with a high incidence in children and adolescents, with high invasiveness and lung metastases. Even after traditional surgical excision, chemoradiotherapy, and comprehensive treatment, the survival rate of patients is still low, and the prognosis is not ideal. As an important part of non-coding RNA family, lncRNA and miRNA have significant regulatory effects on the growth, proliferation, metastasis and apoptosis of osteosarcoma cells. Therefore, exploring the roles of lncRNAs and miRNAs in the occurrence and development of osteosarcoma is of great help for the subsequent diagnosis, treatment, and prognosis of osteosarcoma. This paper mainly reviews the current research progress on the effects and mechanisms of lncRNAs and miRNAs on osteosarcoma cells, in order to provide new ideas for future research on the development process, treatment methods, and prognosis of osteosarcoma.

Machine learning and experimental analyses identified miRNA expression models associated with metastatic osteosarcoma

Osteosarcoma (OS), as the most common primary bone cancer, has a high invasiveness and metastatic potential, therefore, it has a poor prognosis. This study identified early diagnostic biomarkers using miRNA expression profiles associated with osteosarcoma metastasis. In the first step, we used RNA-seq and online microarray data from osteosarcoma tissues and cell lines to identify differentially expressed miRNAs. Then, using seven feature selection algorithms for ranking, the first-ranked miRNAs were selected as input for five machine learning systems. Using network analysis and machine learning algorithms, we developed new diagnostic models that successfully differentiated metastatic osteosarcoma from non-metastatic samples based on newly discovered miRNA signatures. The results showed that miR-34c-3p and miR-154-3p act as the most promising models in the diagnosis of metastatic osteosarcoma. Validation for this model by RT-qPCR in benign tissue and osteosarcoma biopsies confirmed the lower expression of miR-34c-3p and miR-154-3p in OS samples. In addition, a direct correlation between miR-34c-3p expression, miR-154-3p expression and tumor grade was discovered. The combined values of miR-34c-3p and miR-154-3p showed 90 % diagnostic power (AUC = 0.90) for osteosarcoma samples and 85 % (AUC = 0.85) for metastatic osteosarcoma. Adhesion junction and focal adhesion pathways, as well as epithelial-to-mesenchymal transition (EMT) GO terms, were identified as the most significant KEGG and GO terms for the top miRNAs. The findings of this study highlight the potential use of novel miRNA expression signatures for early detection of metastatic osteosarcoma. These findings may help in determining therapeutic approaches with a quantitative and faster method of metastasis detection and also be used in the development of targeted molecular therapy for this aggressive cancer. Further research is needed to confirm the clinical utility of miR-34c-3p and miR-154-3p as diagnostic biomarkers for metastatic osteosarcoma.

Delivery of miRNAs Using Nanoparticles for the Treatment of Osteosarcoma

Osteosarcoma is the predominant primary malignant bone tumor that poses a significant global health challenge. MicroRNAs (miRNAs) that regulate gene expression are associated with osteosarcoma pathogenesis. Thus, miRNAs are potential therapeutic targets for osteosarcoma. Nanoparticles, widely used for targeted drug delivery, facilitate miRNA-based osteosarcoma treatment. Numerous studies have focused on miRNA delivery using nanoparticles to inhibit the progress of osteosarcoma. Polymer-based, lipid-based, inorganic-based nanoparticles and extracellular vesicles were used to deliver miRNAs for the treatment of osteosarcoma. They can be modified to enhance drug loading and delivery capabilities. Also, miRNA delivery was combined with traditional therapies, for example chemotherapy, to treat osteosarcoma. Consequently, miRNA delivery offers promising therapeutic avenues for osteosarcoma, providing renewed hope for patients. This review emphasizes the studies utilizing nanoparticles for miRNA delivery in osteosarcoma treatment, then introduced and summarized the nanoparticles in detail. And it also discusses the prospects for clinical applications.

KNTC1 knockdown inhibits the proliferation and migration of osteosarcoma cells by MCM2

Osteosarcoma (OS) is a common primary malignant bone tumor, and it is necessary to further investigate the molecular mechanism of OS progression. The expression of kinetochore associated protein 1 (KNTC1) and minichromosome maintenance 2 (MCM2) was detected by immunohistochemistry, quantitative PCR (qPCR) and Western blot. Gene knockdown or overexpression cell models were constructed and the proliferation, apoptosis, cell cycle and migration were detected in vitro, besides, xenograft models were established to explore the effects of KNTC1 downregulation in vivo. Public databased and bioinformatics analysis were performed to screen the downstream molecules and determine the expression of MCM2 in cancers. KNTC1 was overexpressed in OS tissues and positively correlated with overall survival of OS patients. KNTC1 knockdown inhibited the proliferation and migration, and arrested G2 phase, and induced apoptosis. Besides, KNTC1 downregulation restricted the xenograft tumor formation. MCM2, one of the coexpressed genes, was highly expressed in sarcoma and downregulated after KNTC1 knockdown. MCM2 overexpression heightened the proliferation and migration ability of OS cells, which was reversed the inhibiting effects of KNTC1 knockdown. KNTC1 was overexpressed in OS and promoted the progression of OS by upregulating MCM2.

DNA Damage-Sensitized metal phenolic nanosynergists potentiate Low-Power phototherapy for osteosarcoma therapy

Non-invasive and efficient photodynamic therapy (PDT) holds great promise to circumvent resistance to traditional osteosarcoma (OS) treatments. Nevertheless, high-power PDT applied in OS often induces photothermogenesis, resulting in normal cells rupture, sustained inflammation and irreversible vascular damage. Despite its relative safety, low-power PDT fails to induce severe DNA damage for insufficient reactive oxygen species (ROS) production. Herein, a non-ROS-dependent DNA damage-sensitizing strategy is introduced in low-power PDT to amplify the therapeutic efficiency of OS, where higher apoptosis is achieved with low laser power. Inspired by the outstanding DNA damage performance of tannic acid (TA), TA-based metal phenolic networks (MPNs) are engineered to encapsulate hydrophobic photosensitizer (purpurin 18) to act as DNA damage-sensitized nanosynergists (TCP NPs). Specially, under low-power laser irradiation, the TCP NPs can boost ROS instantly to trigger mitochondrial dysfunction simultaneously with upregulation of DNA damage levels triggered by TA to reinforce PDT sensitization, evoking potent antitumor effects. In addition, TCP NPs exhibit long-term retention in tumor, greatly benefiting sustained antitumor performances. Overall, this study sheds new light on promoting the sensitivity of low-power PDT by strengthening DNA damage levels and will benefits advanced OS therapy.

ZNF692 promotes osteosarcoma cell proliferation, migration, and invasion through TNK2-mediated activation of the MEK/ERK pathway

BACKGROUND

Osteosarcoma is a diverse and aggressive bone tumor. Driver genes regulating osteosarcoma initiation and progression remains incompletely defined. Zinc finger protein 692 (ZNF692), a kind of Krüppel C2H2 zinc finger transcription factor, exhibited abnormal expression in different types of malignancies and showed a correlation with the clinical prognosis of patients as well as the aggressive characteristics of cancer cells. Nevertheless, its specific role in osteosarcoma is still not well understood.

METHODS

We investigated the dysregulation and clinical significance of ZNF692 in osteosarcoma through bioinformatic method and experimental validation. A range of in vitro assays, including CCK-8, colony formation, EdU incorporation, wound healing, and transwell invasion tests, were conducted to assess the impact of ZNF692 on cell proliferation, migration, and invasion in osteosarcoma. A xenograft mouse model was established to evaluate the effect of ZNF692 on tumor growth in vivo. Western blot assay was used to measure the protein levels of MEK1/2, P-MEK1/2, ERK1/2, and P-ERK1/2 in cells that had been genetically modified to either reduce or increase the expression of ZNF692. The relationship between ZNF692 and tyrosine kinase non-receptor 2 (TNK2) were validated by qRT-PCR, chromatin immunoprecipitation and luciferase reporter assays.

RESULTS

Expression of ZNF692 was increased in both human osteosarcoma tissues and cell lines. Furthermore, the expression of ZNF692 served as an independent predictive biomarker in osteosarcoma. The results of the survival analysis indicated that increased expression of ZNF692 was associated with worse outcome. Downregulation of ZNF692 inhibits the proliferation, migration, and invasion of osteosarcoma cells, whereas upregulation of ZNF692 has the opposite impact. Western blot assay indicates that reducing ZNF692 decreases phosphorylation of MEK1/2 and ERK1/2, whereas increasing ZNF692 expression enhances their phosphorylation. U0126, a potent inhibitor specifically targeting the MEK/ERK signaling pathway, partially counteracts the impact of ZNF692 overexpression on the proliferation, migration, and invasion of osteosarcoma cells. In addition, ZNF692 specifically interacts with the promoter region of TNK2 and stimulates the transcription of TNK2 in osteosarcoma cells. Forcing the expression of TNK2 weakens the inhibitory impact of ZNF692 knockdown on P-MEK1/2 and P-ERK1/2. Similarly, partly inhibiting TNK2 counteracts the enhancing impact of ZNF692 overexpression on the phosphorylation of MEK1/2 and ERK1/2. Functional tests demonstrate that the suppressive effects of ZNF692 knockdown on cell proliferation, migration, and invasion are greatly reduced when TNK2 is overexpressed. In contrast, the reduction of TNK2 hinders the ability of ZNF692 overexpression to enhance cell proliferation, migration, and invasion.

CONCLUSION

ZNF692 promotes the proliferation, migration, and invasion of osteosarcoma cells via the TNK2-dependent stimulation of the MEK/ERK signaling pathway. The ZNF692-TNK2 axis might potentially function as a possible predictive biomarker and a promising target for novel therapeutics in osteosarcoma.

RANK/RANKL axis promotes migration, invasion, and metastasis of osteosarcoma via activating NF-κB pathway

Osteosarcoma (OS) is one of the most prevalent primary bone tumors with a high degree of metastasis and poor prognosis. Epithelial-to-mesenchymal transition (EMT) is a cellular mechanism that contributes to the invasion and metastasis of cancer cells, and OS cells have been reported to exhibit EMT-like characteristics. Our previous studies have shown that the interaction between tumor necrosis factor superfamily member 11 (TNFRSF11A; also known as RANK) and its ligand TNFSF11 (also known as RANKL) promotes the EMT process in breast cancer cells. However, whether the interaction between RANK and RANKL enhances aggressive behavior by inducing EMT in OS cells has not yet been elucidated. In this study, we showed that the interaction between RANK and RANKL increased the migration, invasion, and metastasis of OS cells by promoting EMT. Importantly, we clarified that the RANK/RANKL axis induces EMT by activating the nuclear factor-kappa B (NF-κB) pathway. Furthermore, the NF-κB inhibitor dimethyl fumarate (DMF) suppressed migration, invasion, and EMT in OS cells. Our results suggest that the RANK/RANKL axis may serve as a potential tumor marker and promising therapeutic target for OS metastasis. Furthermore, DMF may have clinical applications in the treatment of lung metastasis in patients with OS.

Unveiling the Protective Role of Melatonin in Osteosarcoma: Current Knowledge and Limitations

Melatonin, an endogenous neurohormone produced by the pineal gland, has received increased interest due to its potential anti-cancer properties. Apart from its well-known role in the sleep-wake cycle, extensive scientific evidence has shown its role in various physiological and pathological processes, such as inflammation. Additionally, melatonin has demonstrated promising potential as an anti-cancer agent as its function includes inhibition of tumorigenesis, induction of apoptosis, and regulation of anti-tumor immune response. Although a precise pathophysiological mechanism is yet to be established, several pathways related to the regulation of cell cycle progression, DNA repair mechanisms, and antioxidant activity have been implicated in the anti-neoplastic potential of melatonin. In the current manuscript, we focus on the potential anti-cancer properties of melatonin and its use in treating and managing pediatric osteosarcoma. This aggressive bone tumor primarily affects children and adolescents and is treated mainly by surgical and radio-oncological interventions, which has improved survival rates among affected individuals. Significant disadvantages to these interventions include disease recurrence, therapy-related toxicity, and severe/debilitating side effects that the patients have to endure, significantly affecting their quality of life. Melatonin has therapeutic effects when used for treating osteosarcoma, attributed to its ability to halt cancer cell proliferation and trigger apoptotic cell death, thereby enhancing chemotherapeutic efficacy. Furthermore, the antioxidative function of melatonin alleviates harmful side effects of chemotherapy-induced oxidative damage, aiding in decreasing therapeutic toxicities. The review concisely explains the many mechanisms by which melatonin targets osteosarcoma, as evidenced by significant results from several in vitro and animal models. Nevertheless, if further explored, human trials remain a challenge that could shed light and support its utility as an adjunctive therapeutic modality for treating osteosarcoma.

miR-488-3p Represses Malignant Behaviors and Facilitates Autophagy of Osteosarcoma Cells by Targeting Neurensin-2

OBJECTIVES

Osteosarcoma (OS) is a primary bone sarcoma that primarily affects children and adolescents and poses significant challenges in terms of treatment. microRNAs (miRNAs) have been implicated in OS cell growth and regulation. This study sought to investigate the role of hsa-miR-488-3p in autophagy and apoptosis of OS cells.

METHODS

The expression of miR-488-3p was examined in normal human osteoblasts and OS cell lines (U2OS, Saos2, and OS 99-1) using RT-qPCR. U2OS cells were transfected with miR-488- 3p-mimic, and cell viability, apoptosis, migration, and invasion were assessed using CCK-8, flow cytometry, and Transwell assays, respectively. Western blotting and immunofluorescence were employed to measure apoptosis- and autophagy-related protein levels, as well as the autophagosome marker LC3. The binding sites between miR-488-3p and neurensin-2 (NRSN2) were predicted using online bioinformatics tools and confirmed by a dual-luciferase assay. Functional rescue experiments were conducted by co-transfecting miR-488-3p-mimic and pcDNA3.1-NRSN2 into U2OS cells to validate the effects of the miR-488-3p/NRSN2 axis on OS cell behaviors. Additionally, 3-MA, an autophagy inhibitor, was used to investigate the relationship between miR- 488-3p/NRSN2 and cell apoptosis and autophagy.

RESULTS

miR-488-3p was found to be downregulated in OS cell lines, and its over-expression inhibited the viability, migration, and invasion while promoting apoptosis of U2OS cells. NRSN2 was identified as a direct target of miR-488-3p. Over-expression of NRSN2 partially counteracted the inhibitory effects of miR-488-3p on malignant behaviors of U2OS cells. Furthermore, miR- 488-3p induced autophagy in U2OS cells through NRSN2-mediated mechanisms. The autophagy inhibitor 3-MA partially reversed the effects of the miR-488-3p/NRSN2 axis in U2OS cells.

CONCLUSION

Our findings demonstrate that miR-488-3p suppresses malignant behaviors and promotes autophagy in OS cells by targeting NRSN2. This study provides insights into the role of miR-488-3p in OS pathogenesis and suggests its potential as a therapeutic target for OS treatment.

Novel roles of PIWI proteins and PIWI-interacting RNAs in human health and diseases

Non-coding RNA has aroused great research interest recently, they play a wide range of biological functions, such as regulating cell cycle, cell proliferation, and intracellular substance metabolism. Piwi-interacting RNAs (piRNAs) are emerging small non-coding RNAs that are 24-31 nucleotides in length. Previous studies on piRNAs were mainly limited to evaluating the binding to the PIWI protein family to play the biological role. However, recent studies have shed more lights on piRNA functions; aberrant piRNAs play unique roles in many human diseases, including diverse lethal cancers. Therefore, understanding the mechanism of piRNAs expression and the specific functional roles of piRNAs in human diseases is crucial for developing its clinical applications. Presently, research on piRNAs mainly focuses on their cancer-specific functions but lacks investigation of their expressions and epigenetic modifications. This review discusses piRNA's biogenesis and functional roles and the recent progress of functions of piRNA/PIWI protein complexes in human diseases. Video Abstract.

Platycodin D inhibits glioblastoma cell proliferation, migration, and invasion by regulating DEPDC1B-mediated epithelial-to-mesenchymal transition

BACKGROUND

Platycodin D (PD) is a potent bioactive constituent in the medicinal herb Platycodon grandiflorum. It has shown anticancer properties, particularly against glioblastoma (GB) and other human malignancies. DEPDC1B (DEP domain-containing protein 1B) is an oncogene associated with epithelial-mesenchymal transition (EMT). It is highly expressed in GB and correlated with tumor grade and patient prognosis. In this study, we investigated whether the antiglioma effect of PD was associated with downregulation of DEPDC1B.

METHODS

Gene expression and clinical data were obtained from the China Glioma Genome Atlas and The Cancer Genome Atlas databases for glioma samples. In vitro experiments were conducted using Cell Counting Kit-8 and Transwell assays to assess the impact of PD on the proliferation, migration, and invasion of GB cells. mRNA and protein expression was evaluated using real-time polymerase chain reaction and western blotting, respectively.

RESULTS

PD exerted inhibitory effects on the proliferation and motility of GB cells. PD downregulated DEPDC1B protein as well as several markers associated with EMT, namely N-cadherin, vimentin, and Snail. The suppressive effects of PD were enhanced when DEPDC1B was knocked down in GB cells, while overexpression of DEPDC1B in cells reversed the inhibitory effects of PD.

CONCLUSION

PD exerts an antiglioma effect by regulating DEPDC1B-mediated EMT.

Expression of E-cadherin and N-cadherin in Epithelial-to-Mesenchymal Transition of Osteosarcoma: A Systematic Review

Osteosarcoma (OS) is a debilitating cancer of the bone that commonly afflicts the young and old. This may be de novo or associated with tumorigenic syndromes. However, many molecular mechanisms are still being uncovered and may offer greater avenues for screening and therapy. Cadherins, including E-cadherin and N-cadherin/vimentin, are involved in epithelial-to-mesenchymal transmission (EMT), which is key for tumor invasion. A study reviewing the relationship between OS and cadherins might elucidate a potential target for therapy and screening. A robust literature review was conducted by searching PubMed with the keywords "osteosarcoma", "cadherin", "e-cadherin" and "n-cadherin". Of a preliminary 266 papers, 25 were included in the final review. Review articles and those without primary data were excluded. Loss of E-cadherin is noted in metastatic cell lines of osteosarcoma. Overexpression of E-cadherin or knockout of N-cadherin/vimentin results in loss of metastatic potential. There are several methods of gene knockout, including CRISPR-Cas9 gene editing, viral vector insertion with micro RNA complementary to long noncoding RNA within gene segments, or proteomic editing. Screening for EMT and genetic treatment of EMT is a possible avenue for the treatment of refractory osteosarcoma. Several studies were conducted ex vivo. Further testing involving in vitro therapy is necessary to validate these methods. Limitations of this study involve a lack of in vivo trials to validate methods.

Circular RNAs in osteosarcoma: An update of recent studies (Review)

Osteosarcoma (OS) prevailing in children and adolescents mainly occurs at the metaphysis of long bones. As it is associated with a high invasive and metastatic ability, resistance to chemotherapy, and a low 5‑year survival rate, the diagnosis and treatment of OS post a global healthy issue. Over the past decades, RNA biology has shed new light onto the pathogenesis of OS. As a type of non‑coding RNAs, circular RNAs (circRNAs) have been found to play crucial roles in cellular activities. Recently, a large number of circRNAs have been identified in OS and some of them have been validated to be functional in OS. In the present review, abnormally expressed and different types of circRNAs in OS are summarized. Functional studies on circRNAs have revealed that circRNAs can regulate gene expression at different levels, such as gene transcription, precursor mRNA splicing, miRNA sponges and translation into proteins/peptides. Mechanistic analyses on circRNAs show that circRNAs can regulate JAK‑STAT3, NF‑κB, PI3K‑AKT, Wnt/β‑catenin signaling pathways during the occurrence and development of OS. Furthermore, the potential clinical applications of circRNAs are also emphasized. The present review focus on the current knowledge on the functions and mechanisms of circRNAs in the pathogenesis of OS, aiming to provide new insight into the OS diagnosis and treatment of OS.

Biodegradable FePS3 nanoplatform for efficient treatment of osteosarcoma by combination of gene and NIR-II photothermal therapy

As a common tumor with high incidence, osteosarcoma possesses extremely poor prognosis and high mortality. Improving the survival of osteosarcoma patients is still a great challenge due to the precipice of advancement in treatment. In this study, a combination strategy of gene therapy and photothermal therapy (PTT) is developed for efficient treatment of osteosarcoma. Two-dimensional (2D) FePS₃ nanosheets are synthesized and functionalized by poly-L-lysine-PEG-folic acid (PPF) to fabricate a multifunctional nanoplatform (FePS@PPF) for further loading microRNAs inhibitor, miR-19a inhibitor (anti-miR-19a). The photothermal conversion efficiency of FePS@PPF is up to 47.1% under irradiation by 1064 nm laser. In vitro study shows that anti-miR-19a can be efficiently internalized into osteosarcoma cells through the protection and delivery of FePS@PPF nanaocarrier, which induces up-regulation of PTEN protein and down-regulation p-AKT protein. After intravenous injection, the FePS@PPF nanoplatform specifically accumulates to tumor site of osteosarcoma-bearing mice. The in vitro and in vivo investigations reveal that the combined PTT-gene therapy displays most significant tumor ablation compared with monotherapy. More importantly, the good biodegradability promotes FePS@PPF to be cleared from body avoiding potential toxicity of long-term retention. Our work not only develops a combined strategy of NIR-II PTT and gene therapy mediated by anti-miR-19a/FePS@PPF but also provides insights into the design and applications of other nanotherapeutic platforms.

A novel 3-miRNA network regulates tumour progression in oral squamous cell carcinoma

BACKGROUND

Late diagnosis is one of the major confounders in oral squamous cell carcinoma (OSCC). Despite recent advances in molecular diagnostics, no disease-specific biomarkers are clinically available for early risk prediction of OSCC. Therefore, it is important to identify robust biomarkers that are detectable using non-invasive liquid biopsy techniques to facilitate the early diagnosis of oral cancer. This study identified potential salivary exosome-derived miRNA biomarkers and crucial miRNA-mRNA networks/underlying mechanisms responsible for OSCC progression.

METHODS

Small RNASeq (n = 23) was performed in order to identify potential miRNA biomarkers in both tissue and salivary exosomes derived from OSCC patients. Further, integrated analysis of The Cancer Genome Atlas (TCGA) datasets (n = 114), qPCR validation on larger patient cohorts (n = 70) and statistical analysis with various clinicopathological parameters was conducted to assess the effectiveness of the identified miRNA signature. miRNA-mRNA networks and pathway analysis was conducted by integrating the transcriptome sequencing and TCGA data. The OECM-1 cell line was transfected with the identified miRNA signature in order to observe its effect on various functional mechanisms such as cell proliferation, cell cycle, apoptosis, invasive as well as migratory potential and the downstream signaling pathways regulated by these miRNA-mRNA networks.

RESULTS

Small RNASeq and TCGA data identified 12 differentially expressed miRNAs in OSCC patients compared to controls. On validating these findings in a larger cohort of patients, miR-140-5p, miR-143-5p, and miR-145-5p were found to be significantly downregulated. This 3-miRNA signature demonstrated higher efficacy in predicting disease progression and clinically correlated with poor prognosis (p < 0.05). Transcriptome, TCGA, and miRNA-mRNA network analysis identified HIF1a, CDH1, CD44, EGFR, and CCND1 as hub genes regulated by the miRNA signature. Further, transfection-mediated upregulation of the 3-miRNA signature significantly decreased cell proliferation, induced apoptosis, resulted in G2/M phase cell cycle arrest and reduced the invasive and migratory potential by reversing the EMT process in the OECM-1 cell line.

CONCLUSIONS

Thus, this study identifies a 3-miRNA signature that can be utilized as a potential biomarker for predicting disease progression of OSCC and uncovers the underlying mechanisms responsible for converting a normal epithelial cell into a malignant phenotype.

Tantalum-Zirconium Co-Doped Metal-Organic Frameworks Sequentially Sensitize Radio-Radiodynamic-Immunotherapy for Metastatic Osteosarcoma

Due to radiation resistance and the immunosuppressive microenvironment of metastatic osteosarcoma, novel radiosensitizers that can sensitize radiotherapy (RT) and antitumor immunity synchronously urgently needed. Here, the authors developed a nanoscale metal-organic framework (MOF, named TZM) by co-doping high-atomic elements Ta and Zr as metal nodes and porphyrinic molecules (tetrakis(4-carboxyphenyl)porphyrin (TCPP)) as a photosensitizing ligand. Given the 3D arrays of ultra-small heavy metals, porous TZM serves as an efficient attenuator absorbing X-ray energy and sensitizing hydroxyl radical generation for RT. Ta-Zr co-doping narrowed the highest occupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap and exhibited close energy levels between the singlet and triplet photoexcited states, facilitating TZM transfer energy to the photosensitizer TCPP to sensitize singlet oxygen (1 O2 ) generation for radiodynamic therapy (RDT). The sensitized RT-RDT effects of TZM elicit a robust antitumor immune response by inducing immunogenic cell death, promoting dendritic cell maturation, and upregulating programmed cell death protein 1 (PD-L1) expression via the cGAS-STING pathway. Furthermore, a combination of TZM, X-ray, and anti-PD-L1 treatments amplify antitumor immunotherapy and efficiently arrest osteosarcoma growth and metastasis. These results indicate that TZM is a promising radiosensitizer for the synergistic RT and immunotherapy of metastatic osteosarcoma.

Zinc oxide nanoparticles inhibit osteosarcoma metastasis by downregulating β-catenin via HIF-1α/BNIP3/LC3B-mediated mitophagy pathway

Osteosarcoma (OS) therapy faces many challenges, especially the poor survival rate once metastasis occurs. Therefore, it is crucial to explore new OS treatment strategies that can efficiently inhibit OS metastasis. Bioactive nanoparticles such as zinc oxide nanoparticles (ZnO NPs) can efficiently inhibit OS growth, however, the effect and mechanisms of them on tumor metastasis are still not clear. In this study, we firstly prepared well-dispersed ZnO NPs and proved that ZnO NPs can inhibit OS metastasis-related malignant behaviors including migration, invasion, and epithelial-mesenchymal transition (EMT). RNA-Seqs found that differentially expressed genes (DEGs) in ZnO NP-treated OS cells were enriched in wingless/integrated (Wnt) and hypoxia-inducible factor-1 (HIF-1) signaling pathway. We further proved that Zn²⁺ released from ZnO NPs induced downregulation of β-catenin expression via HIF-1α/BNIP3/LC3B-mediated mitophagy pathway. ZnO NPs combined with ICG-001, a β-catenin inhibitor, showed a synergistic inhibitory effect on OS lung metastasis and a longer survival time. In addition, tissue microarray (TMA) of OS patients also detected much higher β-catenin expression which indicated the role of β-catenin in OS development. In summary, our current study not only proved that ZnO NPs can inhibit OS metastasis by degrading β-catenin in HIF-1α/BNIP3/LC3B-mediated mitophagy pathway, but also provided a far-reaching potential of ZnO NPs in clinical OS treatment with metastasis.

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Zn²⁺ released from bioactive ZnO NPs trigger OS metastasis inhibition.

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ZnO NPs inhibit OS metastasis through degrading β-catenin expression via HIF-1α/BNIP3/LC3B-mediated mitophagy pathway.

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Tissue microarray of OS patients detected higher β-catenin expression which confirmed the potential of ZnO NPs in clinical.

SIRT2 promotes the viability, invasion and metastasis of osteosarcoma cells by inhibiting the degradation of Snail

Osteosarcomas (OS) are highly metastatic and usually lead to poor outcomes. Epithelial-mesenchymal transition (EMT) is reported to be a critical event in metastasis. SIRT2 exerts dual functions in many different tumors. However, the underlying molecular mechanisms of SIRT2 in osteosarcoma cell metastasis and the question of whether SIRT2 regulates EMT have not been fully explored. In this study, we confirmed that SIRT2 was highly-expressed in human osteosarcoma MG63 and Saos-2 cell lines. The viability, migration and invasion of osteosarcoma cells were inhibited by knockdown of SIRT2 and were enhanced by overexpression of SIRT2. Moreover, SIRT2 positively regulated EMT and upregulated the protein levels of the mesenchymal markers N-cadherin and Vimentin and the levels of MMP2 and MMP9. A xenograft mouse model showed that SIRT2 knockdown in osteosarcoma cells led to reduced tumor growth, decreased expression of mesenchymal markers and impaired lung and liver metastasis in vivo. Furthermore, we showed that SIRT2 interacted with and upregulated the protein level of the EMT-associated transcription factor Snail. SIRT2 inhibited Snail degradation via its deacetylase activity. Knockdown of Snail abrogated the promoting effects of SIRT2 on migration and invasion of osteosarcoma cells. In conclusion, SIRT2 plays a crucial role in osteosarcoma metastasis by inhibiting Snail degradation and may serve as a novel therapeutic target to manage osteosarcoma.

Long non-coding RNA (lncRNA) H19 in human cancer: From proliferation and metastasis to therapy

Initiation and development of cancer depend on multiple factors that mutations in genes and epigenetic level can be considered as important drivers. Epigenetic factors include a large family of members and understanding their function in cancer has been a hot topic. LncRNAs are RNA molecules with no capacity in synthesis of proteins, and they have regulatory functions in cells. LncRNAs are localized in nucleus and cytoplasm, and their abnormal expression is related to development of tumor. This manuscript emphasizes on the role of lncRNA H19 in various cancers and its association with tumor hallmarks. The function of lncRNA H19 in most tumors is oncogenic and therefore, tumor cells increase its expression for promoting their progression. LncRNA H19 contributes to enhancing growth and cell cycle of cancers and by EMT induction, it is able to elevate metastasis rate. Silencing H19 induces apoptotic cell death and disrupts progression of tumors. LncRNA H19 triggers chemo- and radio-resistance in cancer cells. miRNAs are dually upregulated/down-regulated by lncRNA H19 in increasing tumor progression. Anti-cancer agents reduce lncRNA H19 in impairing tumor progression and increasing therapy sensitivity. A number of downstream targets and molecular pathways for lncRNA H19 have been detected in cancers including miRNAs, RUNX1, STAT3, β-catenin, Akt2 and FOXM1. Clinical studies have revealed potential of lncRNA H19 as biomarker and its association with poor prognosis. LncRNA H19 can be transferred to cancer cells via exosomes in enhancing their progression.

cyy260 suppresses the proliferation, migration and tumor growth of osteosarcoma by targeting PDGFR-β signaling pathway

Osteosarcoma (OS) is a group of malignant tumors with high rates of malignancy and metastasis. OS most commonly affects adolescents and young individuals. However, owing to the lack of effective targeted treatments, the 5-year survival rate for OS is still around 20%. Thus, it is essential to develop effective drugs with low toxicity for OS treatment. In the present study, we investigated the antitumor effect and underlying mechanism of cyy260 in OS via suppressing PDGFR-β and its downstream pathway. We demonstrated that cyy260 inhibits OS cell proliferation and promotes apoptosis via inducing DNA damage and causing cell cycle arrest. More importantly, cyy260 also significantly inhibits tumor migration. Further analysis of molecular mechanisms confirmed that PDGFR-β and its downstream AKT, STAT3, and ERK were involved in the cyy260-mediated antitumor effect. Analysis of subcutaneously transplanted tumors in mice showed that cyy260 suppressed tumor cell growth and exhibited low toxicity in vivo. Collectively, these findings proved that cyy260 could serve as a promising PDGFR-β inhibitor for the treatment of OS.

Extracellular vesicles: A new diagnostic biomarker and targeted drug in osteosarcoma

Osteosarcoma (OS) is a primary bone cancer that is highly prevalent among adolescents and adults below the age of 20 years. The prognostic outcome of metastatic OS or relapse is extremely poor; thus, developing new diagnostic and therapeutic strategies for treating OS is necessary. Extracellular vesicles (EVs) ranging from 30–150 nm in diameter are commonly produced in different cells and are found in various types of body fluids. EVs are rich in biologically active components like proteins, lipids, and nucleic acids. They also strongly affect pathophysiological processes by modulating the intercellular signaling pathways and the exchange of biomolecules. Many studies have found that EVs influence the occurrence, development, and metastasis of osteosarcoma. The regulation of inflammatory communication pathways by EVs affects OS and other bone-related pathological conditions, such as osteoarthritis and rheumatoid arthritis. In this study, we reviewed the latest findings related to diagnosis, prognosis prediction, and the development of treatment strategies for OS from the perspective of EVs.

No Effect on Tumorigenesis in MG63 Cells Induced by Co-Cultured Mesenchymal Stem Cells

Osteosarcoma is a kind of bone tumor with an extremely high malignant degree and often occurs in adolescents. Mesenchymal stem cells are believed to play an important role in the microenvironment of osteosarcoma, but whether they promote or inhibit the development of osteosarcoma is controversial. In this study, the coexpression of mesenchymal stem cells (MSCs) with osteosarcoma cell MG63 was used to explore the effect of MSCs on MG63. We found that co-culture of MSCs with MG63 did not affect the proliferation, invasion, and migration of MG63 cells, nor did it significantly affect the epithelial- and glial-mesenchymal transformation of MG63 cells. Therefore, in this study, we obtained a new concept that MSCs neither promote nor inhibit the occurrence and development of osteosarcoma.

Andrographolide inhibits the growth of human osteosarcoma cells by suppressing Wnt/β-catenin, PI3K/AKT and NF-κB signaling pathways

Osteosarcoma (OS) is an aggressive malignant skeletal tumor characterized by an extremely poor prognosis and a high tendency to recur. The frequently used anti-OS chemotherapy regents are often limited by drug resistance and severe adverse events. It is urgent to develop more effective, tolerable and safe drugs for the treatment of OS. Andrographolide (AG), a diterpenoid lactone isolated from Andrographis paniculata, has been proved to possess anti-tumor activity against several human cancer types. In this current study, we evaluated the inhibitory effect of AG on human OS cells and probed the possible mechanism. We found that AG inhibited the proliferation of human OS cells and blocked cell cycle at G2/M phase. Furthermore, AG impeded the migration and invasion, while promoted the apoptosis of human OS cells. Moreover, we found that AG inhibited OS growth and lung metastasis in orthotopic transplantation model. Mechanistically, we demonstrated that AG suppressed the activity of Wnt/β-catenin, PI3K/AKT and NF-κB signaling pathways. Notably, we validated that AG synergized with the inhibitors of Wnt/β-catenin, PI3K/AKT and NF-κB to suppress the proliferation, migration and invasion of human OS cells. Collectively, our study conclusively demonstrates that AG inhibits the growth of human OS cells, thus, may be a promising candidate for the treatment of OS.

Non-coding RNAs regulating epithelial-mesenchymal transition: Research progress in liver disease

Chronic liver injury could gradually progress to liver fibrosis, cirrhosis, and even hepatic carcinoma without effective treatment. The massive production and activation of abnormal cell differentiation is vital to the procession of liver diseases. Epithelial-mesenchymal transformation (EMT) is a biological process in which differentiated epithelial cells lose their epithelial characteristics and acquire mesenchymal cell migration capacity. Emerging evidence suggests that EMT not only occurs in the process of hepatocellular carcinogenesis, but also appears in liver cells transforming to myofibroblasts, a core event of liver disease. Non-coding RNA (ncRNA) such as microRNA (miRNA), long non-coding RNA (lncRNA) and circular RNA (circRNA) are important regulatory factors in EMT, which can regulate target gene expression by binding with RNA single-stranded. Various studies had shown that ncRNA regulation of EMT plays a key role in liver disease development, and many effective ncRNAs have been identified as promising biomarkers for the diagnosis and treatment of liver disease. In this review, we focus on the relationship between the different ncRNAs and EMT as well as the specific molecular mechanism in the liver diseases to enrich the pathological progress of liver diseases and provide reference for the treatment of liver diseases.

A Novel Small Molecular Inhibitor of DNMT1 Enhances the Antitumor Effect of Radiofrequency Ablation in Lung Squamous Cell Carcinoma Cells

Radiofrequency ablation (RFA) is a relatively new and effective therapeutic strategy for treating lung squamous cell carcinomas (LSCCs). However, RFA is rarely used in the clinic for LSCC which still suffers from a lack of effective comprehensive treatment strategies. In the present work, we investigate iDNMT, a novel small molecular inhibitor of DNMT1 with a unique structure. In clinical LSCC specimens, endogenous DNMT1 was positively associated with methylation rates of miR-27-3p's promoter. Moreover, endogenous DNMT1 was negatively correlated with miR-27-3p expression which targets PSEN-1, the catalytic subunit of γ-secretase, which mediates the cleavage and activation of the Notch pathway. We found that DNMT1 increased activation of the Notch pathway in clinical LSCC samples while downregulating miR-27-3p expression and hypermethylation of miR-27-3p's promoter. In addition of inhibiting activation of the Notch pathway by repressing methylation of the miR-27-3p promoter, treatment of LSCC cells with iDNMT1 also enhanced the sensitivity of LSCC tumor tissues to RFA treatment. These data suggest that iDNMT-induced inhibition of DNMT-1 enhances miR-27-3p expression in LSCC to inhibit activation of the Notch pathway. Furthermore, the combination of iDNMT and RFA may be a promising therapeutic strategy for LSCC.

Metastatic Progression of Osteosarcomas: A Review of Current Knowledge of Environmental versus Oncogenic Drivers

Simple Summary

Osteosarcomas are heterogeneous bone tumors with complex genetic and chromosomic alterations. The numerous patients with metastatic osteosarcoma have a very poor prognosis, and only those who can have full surgical resection of the primary tumor and of all the macro metastasis can survive. Despite the recent improvements in prediction and early detection of metastasis, big efforts are still required to understand the specific mechanisms of osteosarcoma metastatic progression, in order to reveal novel therapeutic targets.

Abstract

Metastases of osteosarcomas are heterogeneous. They may grow simultaneously with the primary tumor, during treatment or shortly after, or a long time after the end of the treatment. They occur mainly in lungs but also in bone and various soft tissues. They can have the same histology as the primary tumor or show a shift towards a different differentiation path. However, the metastatic capacities of osteosarcoma cells can be predicted by gene and microRNA signatures. Despite the identification of numerous metastasis-promoting/predicting factors, there is no efficient therapeutic strategy to reduce the number of patients developing a metastatic disease or to cure these metastatic patients, except surgery. Indeed, these patients are generally resistant to the classical chemo- and to immuno-therapy. Hence, the knowledge of specific mechanisms should be extended to reveal novel therapeutic approaches. Recent studies that used DNA and RNA sequencing technologies highlighted complex relations between primary and secondary tumors. The reported results also supported a hierarchical organization of the tumor cell clones, suggesting that cancer stem cells are involved. Because of their chemoresistance, their plasticity, and their ability to modulate the immune environment, the osteosarcoma stem cells could be important players in the metastatic process.

Hypermethylation of the Promoter of miR-338-5p Mediates Aberrant Expression of ETS-1 and Is Correlated With Disease Severity Of Astrocytoma Patients

The pro-oncogene ETS-1 (E26 transformation-specific sequence 1) is a key regulator of the proliferation and invasion of cancer cells. The present work examined the correlation of the aberrant expression of ETS-1 with histological or clinical classification of astrocytoma: grade I (pilocytic astrocytoma), grade II (diffuse astrocytoma), grade III (anaplastic astrocytoma), and grade IV (glioblastoma multiforme). MicroRNA, miR-338-5p, was predicted by an online tool (miRDB) to potentially target the 3' untranslated region of ETS-1; this was confirmed by multi-assays, including western blot experiments or the point mutation of the targeting sites of miR-338-5p in ETS-1's 3'untralation region (3'UTR). The expression of miR-338-5p was negatively associated with that of ETS-1 in astrocytoma, and deficiency of miR-338-5p would mediate aberrant expression of ETS-1 in astrocytoma. Mechanistically, hypermethylation of miR-338-5p by DNA methyltransferase 1 (DNMT1) resulted in repression of miR-338-5p expression and the aberrant expression of ETS-1. Knockdown or deactivation of DNMT1 decreased the methylation rate of the miR-338-5p promoter, increased the expression of miR-338-5p, and repressed the expression of ETS-1 in astrocytoma cell lines U251 and U87. These results indicate that hypermethylation of the miR-338-5p promoter by DNMT1 mediates the aberrant expression of ETS-1 related to disease severity of patients with astrocytoma.

[MiR-671-5p negatively regulates SMAD3 to inhibit migration and invasion of osteosarcoma cells]

OBJECTIVE

To explore the role of miR-671-5p in regulating the migration and invasion of osteosarcoma and the underlying mechanisms.

METHODS

The differentially expressed microRNAs (miRNAs) in osteosarcoma were screened in the NCBI online database, and the target proteins of these miRNAs were predicted and their functions were analyzed. Osteosarcoma cells were transfected with a plasmid overexpressing miR-671-5p, and the transfection efficiency was assessed using quantitative real-time PCR (qRT-PCR). The changes in the migration and invasion of the transfected cells were examined with Transwell assay, and the expressions of proteins related with epithelial-mesenchymal transition (EMT) were detected using Western blotting. Dual-luciferase reporter assay was performed to determine whether the 3'UTR of SMAD3 contained a targeted binding site of miR-671-5p.

RESULTS

MiR-671-5p was significantly down-regulated in both osteosarcoma tissues and osteosarcoma cells (P < 0.05). The osteosarcoma cells overexpressing miR-671-5p showed significantly reduced migration and invasion abilities (P < 0.05) with obviously lowered expressions of EMT-related proteins (P < 0.05). SMAD3 was highly expressed in osteosarcoma cells (P < 0.05), and dual-luciferase reporter assay confirmed the presence of a targeted binding site between miR-671-5p and the 3'UTR of SMAD3 (P < 0.05). In osteosarcoma cells transfected with a SMAD3-overexpressing plasmid (P < 0.05), the high expression of SMAD3 significantly inhibited by miR-671-5p overexpression (P < 0.05). Transwell assay demonstrated that SMAD3 overexpression significantly promoted the migration and invasion of osteosarcoma cells (P < 0.05), and while miR-671-5p overexpression obviously reversed this effect (P < 0.05).

CONCLUSION

MiR-671-5p can inhibit the invasion and migration of osteosarcoma cells by negatively regulating SMAD3.

Sphk1 promotes salivary adenoid cystic carcinoma progression via PI3K/Akt signaling

The progression of salivary adenoid cystic carcinoma (SACC) is closely related to abnormal gene expression. Herein, the role of Sphk1 in SACC was explored. Sphk1 was overexpressed in SACC tissues. In SACC cell lines, Sphk1 induced cell proliferation, inhibited apoptosis, and promoted cell migration. Moreover, Sphk1 overexpression induced up-regulation of the PI3K protein level and AKT phosphorylation level. Rescue assays further showed that activation of the Sphk1 /PI3K/Akt pathway affected various biological functions of SACC cells. Together, these findings suggested that Sphk1 promotes salivary tumorigenesis by activating the PI3K/ Akt pathway, which may provide novel intervention targets for SACC treatment.