SNHG16 promotes tumorigenesis and cisplatin resistance by regulating miR-338-3p/PLK4 pathway in neuroblastoma cells

Comprehensive Analysis Reveals the Molecular Features and Immune Infiltration of PANoptosis-Related Genes in Metabolic Dysfunction-Associated Steatotic Liver Disease

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD), a chronic inflammatory disorder characterized by alcohol-independent hepatic lipid accumulation, remains poorly understood in terms of PANoptosis involvement.

METHODS

We integrated high-throughput sequencing data with bioinformatics to profile differentially expressed genes (DEGs) and immune infiltration patterns in MASLD, identifying PANoptosis-associated DEGs (PANoDEGs). Machine learning algorithms prioritized key PANoDEGs, while ROC curves assessed their diagnostic efficacy. Cellular, animal, and clinical validations confirmed target expression.

RESULTS

Three PANoDEGs (SNHG16, Caspase-6, and Dynamin-1-like protein) exhibited strong MASLD associations and diagnostic significance. Immune profiling revealed elevated M1 macrophages, naïve B cells, and activated natural killer cells in MASLD tissues versus controls. Further experiments verified the expression of the key PANoDEGs.

CONCLUSIONS

This study provides new insights for further studies on the pathogenesis and treatment strategies of PANoptosis in MASLD.

Regulation of immune-mediated chemoresistance in cancer by lncRNAs: an in-depth review of signaling pathways

Resistance to cancer therapies is increasingly recognized as being influenced by long non-coding RNAs (lncRNAs), which are pivotal in regulating cellular functions and gene expression. Elucidating the intricate relationship between lncRNAs and the mechanisms underlying drug resistance is critical for advancing effective therapeutic strategies. This study offers an in-depth review of the regulatory roles lncRNAs play in various signaling and immunological pathways implicated in cancer chemoresistance. lncRNA-mediated influence on drug resistance-related signaling pathways will be presented, including immune evasion mechanisms and other essential signaling cascades. Furthermore, the interplay between lncRNAs and the immune landscape will be dissected, illustrating their substantial impact on the development of chemoresistance. Overall, the potential of lncRNA-mediated signaling networks as a therapeutic strategy to combat cancer resistance has been highlighted. This review reiterates the fundamental role of lncRNAs in chemoresistance and proposes promising avenues for future research and the development of targeted therapeutic interventions.

lncRNAs: New players of cancer drug resistance via targeting ABC transporters

Cancer drug resistance poses a significant obstacle to successful chemotherapy, primarily driven by the activity of ATP-binding cassette (ABC) transporters, which actively efflux chemotherapeutic agents from cancer cells, reducing their intracellular concentrations and therapeutic efficacy. Recent studies have highlighted the pivotal role of long noncoding RNAs (lncRNAs) in regulating this resistance, positioning them as crucial modulators of ABC transporter function. lncRNAs, once considered transcriptional noise, are now recognized for their complex regulatory capabilities at various cellular levels, including chromatin modification, transcription, and post-transcriptional processing. This review synthesizes current research demonstrating how lncRNAs influence cancer drug resistance by modulating the expression and activity of ABC transporters. lncRNAs can act as molecular sponges, sequestering microRNAs that would otherwise downregulate ABC transporter genes. Additionally, they can alter the epigenetic landscape of these genes, affecting their transcriptional activity. Mechanistic insights reveal that lncRNAs contribute to the activity of ABC transporters, thereby altering the efflux of chemotherapeutic drugs and promoting drug resistance. Understanding these interactions provides a new perspective on the molecular basis of chemoresistance, emphasizing the regulatory network of lncRNAs and ABC transporters. This knowledge not only deepens our understanding of the biological mechanisms underlying drug resistance but also suggests novel therapeutic strategies. In conclusion, the intricate interplay between lncRNAs and ABC transporters is crucial for developing innovative solutions to combat cancer drug resistance, underscoring the importance of continued research in this field.

Long noncoding RNAs as potential targets for overcoming chemoresistance in upper gastrointestinal cancers

In the last decade, researchers have paid much attention to the role of noncoding RNA molecules in human diseases. Among the most important of these molecules are LncRNAs, which are RNA molecules with a length of more than 200 nucleotides. LncRNAs can regulate gene expression through various mechanisms, such as binding to DNA sequences and interacting with miRNAs. Studies have shown that LncRNAs may be valuable therapeutic targets in treating various cancers, including upper-gastrointestinal cancers. Upper gastrointestinal cancers, mainly referring to esophageal and gastric cancers, are among the deadliest gastrointestinal cancers. Despite notable advances, traditional chemotherapy remains a common strategy for treating these cancers. However, chemoresistance poses a significant obstacle to the effective treatment of upper gastrointestinal cancers, resulting in a low survival rate. Chemoresistance arises from various events, such as the enhancement of efflux and detoxification of chemotherapy agents, reduction of drug uptake, alteration of drug targeting, reduction of prodrug activation, strengthening of EMT and stemness, and the attenuation of apoptosis in cancerous cells. Tumor microenvironment also plays an important role in chemoresistance. Interestingly, a series of studies have revealed that LncRNAs can influence important mechanisms associated with some of the aforementioned events and may serve as promising targets for mitigating chemoresistance in upper gastrointestinal cancers. In this review paper, following a concise overview of chemoresistance mechanisms in upper gastrointestinal cancers, we will review the most intriguing findings of these investigations in detail.

Exploring the nexus between MYH9 and tumors: novel insights and new therapeutic opportunities

The myosin heavy chain 9 (MYH9) gene, located on human chromosome 22, encodes non-muscle myosin heavy chain IIA (NM IIA). This protein is essential to various cellular events, such as generating intracellular chemomechanical force and facilitating the movement of the actin cytoskeleton. Mutations associated with thrombocytopenia in autosomal dominant diseases first highlighted the significance of the MYH9 gene. In recent years, numerous studies have demonstrated the pivotal roles of MYH9 in various cancers. However, its effects on cancer are intricate and not fully comprehended. Furthermore, the elevated expression of MYH9 in certain malignancies suggests its potential as a target for tumor therapy. Nonetheless, there is a paucity of literature summarizing MYH9's role in tumors and the therapeutic strategies centered on it, necessitating a systematic analysis. This paper comprehensively reviews and analyzes the pertinent literature in this domain, elucidating the fundamental structural characteristics, biological functions, and the nexus between MYH9 and tumors. The mechanisms through which MYH9 contributes to tumor development and its multifaceted roles in the tumorigenic process are also explored. Additionally, we discuss the relationship between MYH9-related diseases (MYH9-RD) and tumors and also summarize tumor therapeutic approaches targeting MYH9. The potential clinical applications of studying the MYH9 gene include improving early diagnosis, clinical staging, and prognosis of tumors. This paper is anticipated to provide novel insights for tumor therapy.

LINC00460 promotes neuroblastoma tumorigenesis and cisplatin resistance by targeting miR-149-5p/DLL1 axis and activating Notch pathway in vitro and in vivo

Long noncoding RNAs (lncRNAs) have been demonstrated to participate in neuroblastoma cisplatin resistance and tumorigenesis. LncRNA LINC00460 was previously reported to play a critical regulatory role in many cancer development. Nevertheless, its role in modulating neuroblastoma cisplatin resistance has not been explored till now. Cisplatin-resistant neuroblastoma cell lines were established by exposing neuroblastoma cell lines to progressively increasing concentrations of cisplatin for 6 months. LINC00460, microRNA (miR)-149-5p, and delta-like ligand 1 (DLL1) mRNA expression was measured through RT-qPCR. The protein levels of DLL1, epithelial-to-mesenchymal transition (EMT) markers, and the Notch signaling-related molecules were measured via western blotting. The IC50 value for cisplatin, cell growth, metastasis and apoptosis were analyzed in cisplatin-resistant neuroblastoma cells. The binding between LINC00460 (or DLL1) and miR-149-5p was validated through dual-luciferase reporter assay. The murine xenograft model was established to perform in vivo assays. LINC00460 and DLL1 levels were elevated, while miR-149-5p level was reduced in cisplatin-resistant neuroblastoma cells. LINC00460 depletion attenuated IC50 values for cisplatin, weakened cell growth, metastasis, and EMT, and enhanced apoptosis in cisplatin-resistant neuroblastoma cells. Mechanically, LINC00460 sponged miR-338-3p to increase DLL1 level, thereby activating Notch signaling pathway. DLL1 overexpression antagonized LINC00460 silencing-induced suppression on neuroblastoma cell cisplatin resistance and malignant behaviors, while such effects were further reversed by treatment with DAPT, the inhibitor of Notch pathway. Additionally, LINC00460 knockdown further augmented cisplatin-induced impairment on tumor growth in vivo. LINC00460 contributes to neuroblastoma cisplatin resistance and tumorigenesis through miR-149-5p/DLL1/Notch pathway, providing new directions to improve the therapeutic efficacy of chemotherapy drugs applied in patients with neuroblastoma.

CRISPR screens reveal convergent targeting strategies against evolutionarily distinct chemoresistance in cancer

Resistance to chemotherapy has been a major hurdle that limits therapeutic benefits for many types of cancer. Here we systematically identify genetic drivers underlying chemoresistance by performing 30 genome-scale CRISPR knockout screens for seven chemotherapeutic agents in multiple cancer cells. Chemoresistance genes vary between conditions primarily due to distinct genetic background and mechanism of action of drugs, manifesting heterogeneous and multiplexed routes towards chemoresistance. By focusing on oxaliplatin and irinotecan resistance in colorectal cancer, we unravel that evolutionarily distinct chemoresistance can share consensus vulnerabilities identified by 26 second-round CRISPR screens with druggable gene library. We further pinpoint PLK4 as a therapeutic target to overcome oxaliplatin resistance in various models via genetic ablation or pharmacological inhibition, highlighting a single-agent strategy to antagonize evolutionarily distinct chemoresistance. Our study not only provides resources and insights into the molecular basis of chemoresistance, but also proposes potential biomarkers and therapeutic strategies against such resistance.

Long Non-Coding RNAs in Neuroblastoma: Pathogenesis, Biomarkers and Therapeutic Targets

Neuroblastoma is the most common malignant extracranial solid tumor of childhood. Recent studies involving the application of advanced high-throughput "omics" techniques have revealed numerous genomic alterations, including aberrant coding-gene transcript levels and dysfunctional pathways, that drive the onset, growth, progression, and treatment resistance of neuroblastoma. Research conducted in the past decade has shown that long non-coding RNAs, once thought to be transcriptomic noise, play key roles in cancer development. With the recent and continuing increase in the amount of evidence for the underlying roles of long non-coding RNAs in neuroblastoma, the potential clinical implications of these RNAs cannot be ignored. In this review, we discuss their biological mechanisms of action in the context of the central driving mechanisms of neuroblastoma, focusing on potential contributions to the diagnosis, prognosis, and treatment of this disease. We also aim to provide a clear, integrated picture of future research opportunities.

Immunological processes of enhancers and suppressors of long non-coding RNAs associated with brain tumors and inflammation

Immunological processes, such as inflammation, can both cause tumor suppression and cancer progression. Moreover, deregulated levels of long non-coding RNA (lncRNA) expression in the brain may cause inflammation and lead to the growth of tumors. Like other biological processes, the immune system's role in cancer is complicated, varies, and can help or hurt the cancer's maintenance. According to research, inflammation and brain cancer are correlated via several signaling pathways. A variety of lncRNAs have recently been revealed to influence cancer by modulating inflammatory pathways. As a result, lncRNAs have the potential to influence carcinogenesis, tumor formation, or tumor suppression via an increase or decrease in inflammation functions. Although the study and targeting of lncRNAs have made great progress in the treatment of cancer, there are definitely limitations and challenges. Using new technologies like nanocarriers and cell-penetrating peptides (CPPs) to target treatments without hurting healthy body tissues has shown to be very effective. In this review article, we have collected significantly related lncRNAs and their inhibitory or stimulating roles in inflammation and brain cancer for the first time. However, there are limitations, such as side effects and damage to normal tissues. With the advancement of new targeting technologies, these lncRNAs may be candidates for the specific targeting therapy of brain cancers by limiting inflammation or stimulating the immune system against them in the future.

NR1D1-transactivated lncRNA NUTM2A-AS1 promotes chemoresistance and immune evasion in neuroblastoma via inhibiting B7-H3 degradation

Neuroblastoma (NB), a common solid tumour in young children originating from the sympathetic nervous system during embryonic development, poses challenges despite therapeutic advances like high-dose chemotherapy and immunotherapy. Some survivors still grapple with severe side effects and drug resistance. The role of lncRNA NUTM2A-AS1 has been explored in various cancers, but its function in drug-resistant NB progression is unclear. Our study found that NUTM2A-AS1 expression in cisplatin-resistant NB cells increased in a time- and dose-dependent manner. Knockdown of NUTM2A-AS1 significantly improved NB cell sensitivity to cisplatin and inhibited metastatic abilities. Additionally, we identified B7-H3, an immune checkpoint-related protein, as a NUTM2A-AS1-associated protein in NB cells. NUTM2A-AS1 was shown to inhibit the protein degradation of B7-H3. Moreover, NUTM2A-AS1 modulated immune evasion in cisplatin-resistant NB cells through B7-H3. Furthermore, NUTM2A-AS1 expression in cisplatin-resistant NB cells was transactivated by NR1D1. In summary, our results unveil the molecular or biological relationship within the NR1D1/NUTM2A-AS1/B7-H3 axis in NB cells under cisplatin treatment, providing an intriguing avenue for fundamental research into cisplatin-resistant NB.

Therapeutic potential of targeting polo-like kinase 4

Polo-like kinase 4 (PLK4), a highly conserved serine/threonine kinase, masterfully regulates centriole duplication in a spatiotemporal manner to ensure the fidelity of centrosome duplication and proper mitosis. Abnormal expression of PLK4 contributes to genomic instability and associates with a poor prognosis in cancer. Inhibition of PLK4 is demonstrated to exhibit significant efficacy against various types of human cancers, further highlighting its potential as a promising therapeutic target for cancer treatment. As such, numerous small-molecule inhibitors with distinct chemical scaffolds targeting PLK4 have been extensively investigated for the treatment of different human cancers, with several undergoing clinical evaluation (e.g., CFI-400945). Here, we review the structure, distribution, and biological functions of PLK4, encapsulate its intricate regulatory mechanisms of expression, and highlighting its multifaceted roles in cancer development and metastasis. Moreover, the recent advancements of PLK4 inhibitors in patent or literature are summarized, and their therapeutic potential as monotherapies or combination therapies with other anticancer agents are also discussed.

LncRNA ZNF674-AS1 drives cell growth and inhibits cisplatin-induced pyroptosis via up-regulating CA9 in neuroblastoma

Neuroblastoma (NB) is a challenging pediatric extracranial solid tumor characterized by a poor prognosis and resistance to chemotherapy. Identifying targets to enhance chemotherapy sensitivity in NB is of utmost importance. Increasing evidence implicates long noncoding RNAs (lncRNAs) play important roles in cancer, but their functional roles remain largely unexplored. Here, we analyzed our RNA sequencing data and identified the upregulated lncRNA ZNF674-AS1 in chemotherapy non-responsive NB patients. Elevated ZNF674-AS1 expression is associated with poor prognosis and high-risk NB. Importantly, targeting ZNF674-AS1 expression in NB cells suppressed tumor growth in vivo. Further functional studies have revealed that ZNF674-AS1 constrains cisplatin sensitivity by suppressing pyroptosis and promoting cell proliferation. Moreover, ZNF674-AS1 primarily relies on CA9 to fulfill its functions on cisplatin resistance. High CA9 levels were associated with high-risk NB and predicted poor patient outcomes. Mechanistically, ZNF674-AS1 directly interacted with the RNA binding protein IGF2BP3 to enhance the stability of CA9 mRNA by binding with CA9 transcript, leading to elevated CA9 expression. As a novel regulator of CA9, IGF2BP3 positively upregulated CA9 expression. Together, these results expand our understanding of the cancer-associated function of lncRNAs, highlighting the ZNF674-AS1/IGF2BP3/CA9 axis as a constituting regulatory mode in NB tumor growth and cisplatin resistance. These insights reveal the pivotal role of ZNF674-AS1 inhibition in recovering cisplatin sensitivity, thus providing potential therapeutic targets for NB treatment.

Role of non-coding RNAs in neuroblastoma

Neuroblastoma is known as the most prevalent extracranial malignancy in childhood with a neural crest origin. It has been widely accepted that non-coding RNAs (ncRNAs) play important roles in many types of cancer, including glioma and gastrointestinal cancers. They may regulate the cancer gene network. According to recent sequencing and profiling studies, ncRNAs genes are deregulated in human cancers via deletion, amplification, abnormal epigenetic, or transcriptional regulation. Disturbances in the expression of ncRNAs may act either as oncogenes or as anti-tumor suppressor genes, and can lead to the induction of cancer hallmarks. ncRNAs can be secreted from tumor cells inside exosomes, where they can be transferred to other cells to affect their function. However, these topics still need more study to clarify their exact roles, so the present review addresses different roles and functions of ncRNAs in neuroblastoma.

Circ_RBM23 knockdown suppresses chemoresistance, proliferation, migration and invasion of sorafenib-resistant HCC cells through miR-338-3p/RAB1B axis

BACKGROUND

Circular RNA RNA-binding motif protein 23 (circ_RBM23; ID: hsa_circ_0000524) is a novel regulator in hepatocellular carcinoma (HCC). Herein, we planned to investigate its role in sorafenib resistance in HCC.

METHOD

Levels of circ_RBM23, microRNA (miR)-338-3p, Ras-related GTPase-trafficking protein (RAB1B), Snail and E-cadherin were detected by real-time quantitative PCR and western blotting. Sorafenib resistant (SR) HCC cells (Huh7/SR and SK-HEP-1/SR) were established by acquisition of sorafenib resistance, and cell functions were measured by MTT assay, Edu assay, colony formation assay, apoptosis assay, transwell assay, and in vivo xenograft formation assay. Crosslink between miR-338-3p and circ_RBM23 or RAB1B was confirmed by bioinformatics analysis and dual-luciferase reporter assay.

RESULTS

Circ_RBM23 upregulation was discovered in the tissues of SR patients and SR cells, which was accompanied with miR-338-3p downregulation and RAB1B upregulation. The 50% inhibitory concentration (IC₅₀) of sorafenib in SR cells was greatly suppressed by interfering circ_RBM23 or reinforcing miR-338-3p, allied with this was the inhibition of EdU-positive cell rate, colony formation and migration/invasion abilities under sorafenib treatment, as well as the enhancement of apoptotic rate. Moreover, circ_RBM23 inhibition delayed tumor growth of Huh7/SR cells under sorfanib treatment in vivo.

CONCLUSION

Circ_RBM23 promoted chemoresistance, malignant proliferation, migration and invasion of SR HCC cells by modulating miR-338-3p/RAB1B axis.

Multiple Myeloma Side Population Cells Promote Dexamethasone Resistance of Main Population Cells through Exosome Metastasis of LncRNA SNHG16

Background

The emergence of dexamethasone (Dex) resistance limits its efficacy. Side population (SP) cells in MM have strong tumorigenicity. Nevertheless, the detailed effect by which SP cells regulate Dex resistance in MP cells has not been completely verified and needs to be further investigated.

Methods

SP and MP cells were sorted from RPMI-8226. mRNA expression and cell viability were analyzed using quantitative real-time PCR (qRT-PCR) and MTS assays, respectively. The presence of exosomal lncRNA SNHG16 was verified by transmission electron microscopy, differential ultracentrifugation, and qRT-PCR. Protein expression levels were measured using western blotting. Gain or loss function analyses were performed to demonstrate the role of SNHG16 in the Dex resistance of MP cells.

Results

Dex resistance of SP cells was remarkably stronger than that of MP cells. Compared with MP cells, the survival rate and Dex resistance of MP cells cotreated with SP cell-derived exosomes were increased. SNHG16 expression was significantly enhanced in SP cell-derived exosomes compared to MP cell-derived exosomes. SNHG16 expression was remarkably increased in MP cells transfected with OE-SNHG16 vectors, and Dex resistance of MP cells was enhanced. When SNHG16 was silenced in SP cells, the SNHG16 expression was downregulated in both SP cells and SP cell-derived exosomes. SNHG16 expression and Dex resistance were both remarkably downregulated in MP cells treated with SP-si-SNHG16-exosomes compared to MP cells treated with SP-si-NC-exosomes.

Conclusion

MM SP cells promote Dex resistance in MP cells through exosome metastasis of SNHG16.

Tamoxifen resistance-related ceRNA network for breast cancer

Background: Tamoxifen (TMX) is one of the most widely used drugs to treat breast cancer (BC). However, acquired drug resistance is still a major obstacle to its application, rendering it crucial to explore the mechanisms of TMX resistance in BC. This aims of this study were to identify the mechanisms of TMX resistance and construct ceRNA regulatory networks in breast cancer. Methods: GEO2R was used to screen for differentially expressed mRNAs (DEmRNAs) leading to drug resistance in BC cells. MiRTarbase and miRNet were used to predict miRNAs and lncRNAs upstream, and the competing endogenous RNA (ceRNA) regulatory network of BC cell resistance was constructed by starBase. We used the Kaplan-Meier plotter and Gene Expression Profiling Interactive Analysis (GEPIA) to analyze the expression and prognostic differences of genes in the ceRNA network with core axis, and qRT-PCR was used to further verify the above conclusions. Results: We found that 21 DEmRNAs were upregulated and 43 DEmRNA downregulated in drug-resistant BC cells. DEmRNAs were noticeably enriched in pathways relevant to cancer. We then constructed a protein-protein interaction (PPI) network based on the STRING database and defined 10 top-ranked hub genes among the upregulated and downregulated DEmRNAs. The 20 DEmRNAs were predicted to obtain 113 upstream miRNAs and 501 lncRNAs. Among them, 7 mRNAs, 22 lncRNAs, and 11 miRNAs were used to structure the ceRNA regulatory network of drug resistance in BC cells. 4 mRNAs, 4 lncRNAs, and 3 miRNAs were detected by GEPIA and the Kaplan-Meier plotter to be significantly associated with BC expression and prognosis. The differential expression of the genes in BC cells was confirmed by qRT-PCR. Conclusion: The ceRNA regulatory network of TMX-resistant BC was successfully constructed and confirmed. This will provide an important resource for finding therapeutic targets for TMX resistance, where the discovery of candidate conventional mechanisms can aid clinical decision-making. In addition, this resource will help discover the mechanisms behind this type of resistance.

Sevoflurane reverses cisplatin resistance in neuroblastoma cells through the linc00473/miR-490-5p/AKT1 axis

OBJECTIVES

To determine whether sevoflurane regulates cisplatin resistance in neuroblastoma cells.

METHODS

The SH-SY5Y cell line with cisplatin-resistant phenotype (SH-SY5Y-SR) was generated. Cells were co-treated with sevoflurane and cisplatin to seek the sevoflurane function on cisplatin resistance. Key targets of sevoflurane treatment were determined using sequencing (ribonucleic acid [RNA-seq]). Cells were then transfected with specific vectors. Linc00473 and microRNA-490-5p (miR-490-5p) levels were detected using reverse transcriptase quantitative real-time reverse transcription PCR (RT-qPCR). Linc00473-miR-490-5p binding was confirmed using a luciferase reporter-gene assay. After treatment, cell proliferation, viability, and caspase-3 activity were measured to determine the effects of treatment on tumor cells. Each experimental result is based on three independent experiments.

RESULTS

Co-treatment with sevoflurane and cisplatin markedly improved the sensitivity of SH-SY5Y-SR cells to cisplatin, which inhibited the occurrence of cisplatin resistance. The RNA-sequencing analysis and RT-qPCR showed that sevoflurane inhibited linc00473 expression. Overexpression of linc00473 promoted cell proliferation, inhibited apoptosis, and promoted cisplatin resistance. The linc00473/miR-490-5p/V-akt murine thymoma viral oncogene homolog 1 (AKT1) axis was found to mediate the regulatory effects of sevoflurane on cisplatin resistance.

CONCLUSION

Sevoflurane has great clinical potential against cisplatin-resistant tumors. Further animal experiments and clinical trials are required to achieve this goal.

Long non-coding RNA SNHG16 promotes human placenta-derived mesenchymal stem cell proliferation capacity through the PI3K/AKT pathway under hypoxia

BACKGROUND

The effect of hypoxia on mesenchymal stem cells (MSCs) is an emerging topic in MSC biology. Although long non-coding RNAs (lncRNAs) and messenger RNAs (mRNAs) are reported to play a critical role in regulating the biological characteristics of MSCs, their specific expression and co-expression profiles in human placenta-derived MSCs (hP-MSCs) under hypoxia and the underlying mech anisms of lncRNAs in hP-MSC biology are unknown.

AIM

To reveal the specific expression profiles of lncRNAs in hP-MSCs under hypoxia and initially explored the possible mechanism of lncRNAs on hP-MSC biology.

METHODS

Here, we used a multigas incubator (92.5% N2, 5% CO2, and 2.5% O2) to mimic the hypoxia condition and observed that hypoxic culture significantly promoted the proliferation potential of hP-MSCs. RNA sequencing technology was applied to identify the exact expression profiles of lncRNAs and mRNAs under hypoxia.

RESULTS

We identified 289 differentially expressed lncRNAs and 240 differentially expressed mRNAs between the hypoxia and normoxia groups. Among them, the lncRNA SNHG16 was upregulated under hypoxia, which was also validated by reverse transcription-polymerase chain reaction. SNHG16 was confirmed to affect hP-MSC proliferation rates using a SNHG16 knockdown model. SNHG16 overexpression could significantly enhance the proliferation capacity of hP-MSCs, activate the PI3K/AKT pathway, and upregulate the expression of cell cycle-related proteins.

CONCLUSION

Our results revealed the specific expression characteristics of lncRNAs and mRNAs in hypoxia-cultured hP-MSCs and that lncRNA SNHG16 can promote hP-MSC proliferation through the PI3K/AKT pathway.

Long non-coding RNA SNHG16 decreased SMAD4 to induce gemcitabine resistance in pancreatic cancer via EZH2-mediated epigenetic modification

Gemcitabine resistance (GR) in pancreatic cancer (PC) results in poor patient outcomes. SMAD family member (Smad4) dysregulation is a significant role of GR in PC, and EZH2 is involved in Smad4 expression in tumor progression. Interestingly, lncRNA small nucleolar RNA host gene 16 (SNHG16) might interact with EZH2, indicating a potential pathway to overcome gemcitabine-resistant PC progression. We investigated the role of the SNHG16/EZH2/Smad4 pathway in gemcitabine-resistant PC cells (PANC-1/GR and SW1990/GR). First, we found that SNHG16 was upregulated both in wild-type PC cells and in gemcitabine-resistant PC cells. SNHG16 overexpression reduced gemcitabine cytotoxicity and apoptosis in PC cells. Meanwhile, SNHG16 upregulation caused p-Akt elevation and Smad4 reduction. However, SNHG16 silencing induced the opposite trend. Then, we found that EZH2 was enriched in SNHG16 based on RIP and RNA pulldown. In particular, SNHG16 overexpression promoted the interaction between EZH2 and the Smad4 promoter according to Chromatin immunoprecipitation-quantitative polymerase chain reaction. Finally, both EZH2 inhibition and Smad4 upregulation increased gemcitabine cytotoxicity and apoptosis in PC cells during SNHG16 overexpression. Moreover, both treatments decreased p-Akt and increased Smad4. Collectively, lncRNA SNHG16 decreased Smad4 to induce GR in PC via EZH2-mediated epigenetic modification.

KLF5 promotes KIF1A expression through transcriptional repression of microRNA-338 in the development of pediatric neuroblastoma

BACKGROUND

Neuroblastoma (NB) comprises about 8-10% of pediatric cancers, and microRNA (miR)-338 downregulation has been implicated in NB. However, the underlying molecular mechanism remains largely unclear. The main goal of this study is to probe the regulatory role of miR-338 and the upstream and downstream biomolecules involved in NB.

METHODS

The differentially expressed miRNAs were screened by analyzing the NB gene expression microarray GSE121513 from the GEO database, and the differences in expression of the screened miRNAs were verified in clinically collected NB tissues versus dorsal root ganglions. Subsequently, the relationship between the miR-338 expression and NB cell growth was validated in vitro and in vivo, and the upstream and downstream regulatory mechanisms of miR-338 were further analyzed by bioinformatics. Functional rescue experiments were used to verify their effects on NB cell growth.

RESULTS

miR-338 expressed poorly in NB tissues, and overexpression of miR-338 significantly inhibited NB cell growth in vitro and in vivo. The prediction results showed that miR-338 could target KIF1A, and miR-338 expression was negatively correlated with the expression of KIF1A. We further found that miR-338 was transcriptionally regulated by the transcription factor KLF5. Overexpression of KLF5 or KIF1A significantly attenuated the inhibitory effect of miR-338 mimic on NB cell growth. Finally, miR-338 blocked the Hedgehog signaling pathway by inhibiting the expression of KIF1A.

CONCLUSION

Overexpression of KLF5 reduced expression of miR-338, which in turn increased the expression of KIF1A and activated the Hedgehog signaling pathway, leading to the progression of NB.

SNHG25 facilitates SNORA50C accumulation to stabilize HDAC1 in neuroblastoma cells

Increasing studies have pointed out that small nucleolar RNAs (snoRNAs) and their host genes (SNHGs) have multi-functional roles in cancer progression. Bioinformatics analysis revealed the importance of snoRNA host gene 25 (SNHG25) in neuroblastoma (NB). Hence, we further explored the function and molecular mechanism of SNHG25 in NB. Our study revealed that SNHG25 expression was upregulated in NB cells. Through loss-of-function assays, we discovered that silencing of SNHG25 suppressed NB cell proliferation, invasion, and migration. Moreover, we found that SNHG25 positively regulated snoRNA small nucleolar RNA, H/ACA box 50 C (SNORA50C) in NB cells, and SNORA50C depletion had the same function as SNHG25 silencing in NB cells. Moreover, we proved that SNHG25 recruited dyskerin pseudouridine synthase 1 (DKC1) to facilitate SNORA50C accumulation and associated small nucleolar ribonucleoprotein (snoRNP) assembly. In addition, it was manifested that SNHG25 relied on SNORA50C to inhibit ubiquitination of histone deacetylase 1 (HDAC1), thereby elevating HDAC1 expression in NB cells. Further, HDAC1 was proven to be a tumor-facilitator in NB, and SNORA50C contributed to NB cell growth and migration through the HDAC1-mediated pathway. In vivo xenograft experiments further supported that SNHG25 promoted NB progression through SNORA50C/HDAC1 pathway. Our study might provide a novel sight for NB treatment.

PLK4 inhibitor plus bortezomib exhibits a synergistic effect on treating multiple myeloma via inactivating PI3K/AKT signaling

OBJECTIVE

The anti-tumor effect of polo-like kinase 4 (PLK4) inhibitor has been explored in several neoplasms, while its synergy with bortezomib in multiple myeloma (MM) remains elusive. Hence, the present study aimed to investigate the effect of PLK4 inhibitor on the sensitivity of MM to bortezomib treatment and its underlying mechanism.

METHODS

MM cell lines (RPMI-8226 and U266) were cultured in different concentrations of CFI-400945 (PLK4 inhibitor), bortezomib, or their combination. Subsequently, 740 Y-P (PI3K activator) was added in the combination of CFI-400945 and bortezomib. Besides, cell viability and apoptosis were measured by CCK-8 reagent and TUNEL apoptosis kit, separately; meanwhile, western blot was carried out for detecting PLK4, p-PI3K, PI3K, p-AKT, and AKT.

RESULTS

CFI-400945 and bortezomib decreased the cell viability in dose-dependent manners in MM cell lines, respectively. The combination of different concentrations of CFI-400945 and bortezomib reduced cell viability compared with monotherapy in MM cell lines (all P < 0.05). Interestingly, 200 nM CFI-400945 and 4 nM bortezomib showed the maximum synergy in MM cell lines. Furthermore, 200 nM CFI-400945 plus 4 nM bortezomib showed a better effect on decreasing cell viability and promoting cell apoptosis than CFI-400945 or bortezomib monotherapy in MM cells cell lines (all P < 0.05). Moreover, 740 Y-P alleviated the effect of bortezomib and CFI-400945 on PI3K/AKT signaling, cell viability, and apoptosis in MM cell lines.

CONCLUSIONS

PLK4 inhibitor plus bortezomib shows synergy in decreasing cell viability and enhancing cell apoptosis via repressing PI3K/AKT signaling in MM.

Fraxetin down-regulates polo-like kinase 4 (PLK4) to inhibit proliferation, migration and invasion of prostate cancer cells through the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (Akt) pathway

Fraxetin, a natural product isolated from herb Cortex Fraxini, has been demonstrated to exhibit anti-cancer effects on various cancers. The aim of this work is to investigate the anti-tumor effect of Fraxetin in prostate cancer and the potential mechanisms. In this study, the prostatic epithelial cell RWPE-1 and prostate cancer cell DU145 were exposed to Fraxetin (10, 20, 40, and 80 μM) to detect the changes in cell viability using cell counting kit-8 (CCK-8) assay. Fraxetin (10, 20, and 40 μM) was utilized to treat DU145 cell, then the changes in cell proliferation, apoptosis, migration, and invasion were assessed. Western blot assay was employed to detect the expression of proteins that participate in the above cellular processes as well as Polo-like kinase 4 (PLK4), phosphatidylinositol 3-kinase (PI3K). In addition to 40 μM Fraxetin treatment, DU145 cells were overexpressed with PLK4, and then the above experiments were repeated. Results revealed that Fraxetin markedly decreased DU145 cell viability, but didn’t affect the cell viability of RWPE-1. Fraxetin suppressed cell proliferation, migration, invasion, and induced apoptosis of DU145 cells in a concentration-dependent manner. Furthermore, the expression of PLK4 and phosphorylated PI3K and protein kinase B (Akt) were reduced upon Fraxetin treatment. Finally, PLK4 overexpression significantly reversed all the effects of Fraxetin on DU145 cells. Collectively, Fraxetin acted as a cancer suppressor in prostate cancer through inhibiting PLK4 expression thereby inactivating PI3K/Akt signaling.

The role of ncRNAs in neuroblastoma: mechanisms, biomarkers and therapeutic targets

Neuroblastoma (NB) is a malignant tumor in young children that originates from the neural crest of the sympathetic nervous system. Generally, NB occurs in the adrenal glands, but it can also affect the nerve tissues of the neck, chest, abdomen, and pelvis. Understanding the pathophysiology of NB and developing novel therapeutic approaches are critical. Noncoding RNAs (ncRNAs) are associated with crucial aspects of pathology, metastasis and drug resistance in NB. Here, we summarized the pretranscriptional, transcriptional and posttranscriptional regulatory mechanisms of ncRNAs involved in NB, especially focusing on regulatory pathways. Furthermore, ncRNAs with the potential to serve as biomarkers for risk stratification, drug resistance and therapeutic targets are also discussed, highlighting the clinical application of ncRNAs in NB.

SPRR3, a novel miR‑338‑3p target, regulates the malignant progression of clear cell renal cell carcinoma in vitro via the PI3K/Akt signaling pathway

Clear cell renal cell carcinoma (ccRCC) is the most common type of renal cell carcinoma and has a poor prognosis. However, its underlying mechanisms remain unclear. The present study aimed to evaluate the role of small proline-rich repeat protein 3 (SPRR3) in the proliferation, migration and invasion of ccRCC cells and to investigate its upstream and downstream regulatory mechanisms. Survival analysis was performed using the UALCAN website based on the The Cancer Genome Atlas database. Normal renal cell line HK-2 and ccRCC cell lines (786-O, CaKi-1 and UMRC-2) were used. Reverse transcription-quantitative PCR (RT-qPCR) was used to detect mRNA and microRNA (miRNA) levels. Western blotting was used to detect protein levels. Cell Counting Kit-8 and colony formation assays, a wound healing assay and a Transwell invasion assay were used to assess the proliferation, migration and invasion of ccRCC cells, respectively. Transfection of overexpression plasmids and small interfering RNAs were used to upregulate and knockdown SPRR3 expression, respectively. Transfection of miRNA-mimics was used to overexpress miR-338-3p. A luciferase reporter gene assay was used to verify the predicted binding relationship between SPRR3 mRNA and miR-338-3p. The results indicated the following: i) SPRR3 was a risk factor for the survival of patients with ccRCC, and was upregulated in ccRCC cell lines; ii) SPRR3 promoted the proliferation, migration and invasion of ccRCC cells; iii) SPRR3 regulated the tumor phenotypes of ccRCC cells via the PI3K/Akt pathway; iv) miR-338-3p directly targeted SPRR3 mRNA and negatively regulated SPRR3 expression; and v) miR-338-3p inhibited the PI3K/Akt pathway and the tumor phenotypes of ccRCC cells by downregulating SPRR3. In conclusion, SPRR3, as a novel target of miR-338-3p, regulated the proliferation, migration and invasion of ccRCC cells via the PI3K/Akt pathway; this finding not only enriches our understanding of the mechanism underlying ccRCC development, but also demonstrates a potential novel therapeutic target for this disease.

A Review on the Role of Small Nucleolar RNA Host Gene 6 Long Non-coding RNAs in the Carcinogenic Processes

Being located on 17q25.1, small nucleolar RNA host gene 6 (SNHG16) is a member of SNHG family of long non-coding RNAs (lncRNA) with 4 exons and 13 splice variants. This lncRNA serves as a sponge for a variety of miRNAs, namely miR-520a-3p, miR-4500, miR-146a miR-16–5p, miR-98, let-7a-5p, hsa-miR-93, miR-17-5p, miR-186, miR-302a-3p, miR-605-3p, miR-140-5p, miR-195, let-7b-5p, miR-16, miR-340, miR-1301, miR-205, miR-488, miR-1285-3p, miR-146a-5p, and miR-124-3p. This lncRNA can affect activity of TGF-β1/SMAD5, mTOR, NF-κB, Wnt, RAS/RAF/MEK/ERK and PI3K/AKT pathways. Almost all studies have reported oncogenic effect of SNHG16 in diverse cell types. Here, we explain the results of studies about the oncogenic role of SNHG16 according to three distinct sets of evidence, i.e., in vitro, animal, and clinical evidence.

Resistance to platinum-based cancer drugs: a special focus on epigenetic mechanisms

Chemoresistance is a significant clinical challenge, limiting the drug response in cancer. Several mechanisms associated with drug resistance have been characterized, and the role of epigenetics in generating resistance to platinum-based drugs has been clarified. Epigenetic mechanisms such as DNA methylation, histone modification, long noncoding RNA, and microRNA affect the expression of genes implicated in absorption, distribution, metabolism and excretion (ADME) of drugs, and other non-ADME genes that encode enzymes involved in the processes of cell proliferation, DNA repair, apoptosis and signal transduction key in the development of chemoresistance in cancer, specifically in platinum-based drugs. This review summarizes current discoveries in epigenetic regulation implicated in platinum drug resistance in cancer and the main clinical trials based on epigenetic therapy, evaluating their potential synergy with platinum-based drugs.

Nanotherapeutic approaches to target mitochondria in cancer

Treatment of cancer cells exemplifies a difficult test in the light of challenges associated with the nature of cancer cells and the severe side effects too. After making a large number of trials using both traditional and advanced therapies (immunotherapy and hormone therapy), approaches to design new therapies have reached a saturation level. However, nanotechnology-based approaches exhibit higher efficacy and great potential to bypass many of such therapeutic limitations. Because of their higher target specificity, the use of nanoparticles offers incredible potential in cancer therapeutics. Mitochondria, acting as a factory of energy production in cells, reveal an important role in the death as well as the survival of cells. Because of its significant involvement in the proliferation of cancer cells, it is being regarded as an important target for cancer therapeutics. Numerous studies reveal that nanotechnology-based approaches to directly target the mitochondria may help in improving the survival rate of cancer patients. In the current study, we have detailed the significance of mitochondria in the development of cancer phenotype, as well as indicated it as the potential targets for cancer therapy. Our study further highlights the importance of different nanoparticle-based approaches to target mitochondria of cancer cells and the associated outcomes of different studies. Though, nanotechnology-based approaches to target mitochondria of cancer cells demonstrate a potential and efficient way in cancer therapeutics. Yet, further study is needed to overcome the linked limitations.

Role of Long Non-Coding RNAs in Conferring Resistance in Tumors of the Nervous System

Tumors of the nervous system can be originated from several locations. They mostly have high mortality and morbidity rate. The emergence of resistance to chemotherapeutic agents is a hurdle in the treatment of patients. Long non-coding RNAs (lncRNAs) have been shown to influence the response of glioblastoma/glioma and neuroblastoma to chemotherapeutic agents. MALAT1, NEAT1, and H19 are among lncRNAs that affect the response of glioma/glioblastoma to chemotherapy. As well as that, NORAD, SNHG7, and SNHG16 have been shown to be involved in conferring this phenotype in neuroblastoma. Prior identification of expression amounts of certain lncRNAs would help in the better design of therapeutic regimens. In the current manuscript, we summarize the impact of lncRNAs on chemoresistance in glioma/glioblastoma and neuroblastoma.

A minor review of microRNA-338 exploring the insights of its function in tumorigenesis

MicroRNAs(miRNAs) are small non-coding RNAs which have a critical role in various biological processes via direct binding and post-transcriptionally regulating targeted genes expression. More than one-half of human genes were regulated by miRNAs and their aberrant expression was detected in various human diseases, including cancers. miRNA-338 is a new identified miRNA and increasing evidence show that miRNA-338 participates in the progression of lots of cancers, such as lung cancer, hepatocellular cancer, breast cancer, glioma, and so on. Although a range of targets and signaling pathways such as MACC1 and Wnt/β-catenin signaling pathway were illustrated to be regulated by miRNA-338, which functions in tumor progression are still ambiguous and the underlying molecular mechanisms are also unclear. Herein, we reviewed the latest studies in miRNA-338 and summarized its roles in different type of human tumors, which might provide us new idea for further investigations and potential targeted therapy.

An Overview of Long Non-Coding (lnc)RNAs in Neuroblastoma

Neuroblastoma (NB) is a heterogeneous developmental tumor occurring in childhood, which arises from the embryonic sympathoadrenal cells of the neural crest. Although the recent progress that has been done on this tumor, the mechanisms involved in NB are still partially unknown. Despite some genetic aberrations having been identified, the sporadic cases represent the majority. Due to its wide heterogeneity in clinical behavior and etiology, NB represents a challenge in terms of prevention and treatment. Since a definitive therapy is lacking so far, there is an urgent necessity to unveil the molecular mechanisms behind NB onset and progression to develop new therapeutic approaches. Long non-coding RNAs (lncRNAs) are a group of RNAs longer than 200 nucleotides. Whether lncRNAs are destined to become a protein or not, they exert multiple biological functions such as regulating gene expression and functions. In recent decades, different research has highlighted the possible role of lncRNAs in the pathogenesis of many diseases, including cancer. Moreover, lncRNAs may represent potential markers or targets for diagnosis and treatment of diseases. This mini-review aimed to briefly summarize the most recent findings on the involvement of some lncRNAs in NB disease by focusing on their mechanisms of action and possible role in unveiling NB onset and progression.

Elucidating Role of Reactive Oxygen Species (ROS) in Cisplatin Chemotherapy: A Focus on Molecular Pathways and Possible Therapeutic Strategies

The failure of chemotherapy is a major challenge nowadays, and in order to ensure effective treatment of cancer patients, it is of great importance to reveal the molecular pathways and mechanisms involved in chemoresistance. Cisplatin (CP) is a platinum-containing drug with anti-tumor activity against different cancers in both pre-clinical and clinical studies. However, drug resistance has restricted its potential in the treatment of cancer patients. CP can promote levels of free radicals, particularly reactive oxygen species (ROS) to induce cell death. Due to the double-edged sword role of ROS in cancer as a pro-survival or pro-death mechanism, ROS can result in CP resistance. In the present review, association of ROS with CP sensitivity/resistance is discussed, and in particular, how molecular pathways, both upstream and downstream targets, can affect the response of cancer cells to CP chemotherapy. Furthermore, anti-tumor compounds, such as curcumin, emodin, chloroquine that regulate ROS and related molecular pathways in increasing CP sensitivity are described. Nanoparticles can provide co-delivery of CP with anti-tumor agents and by mediating photodynamic therapy, and induce ROS overgeneration to trigger CP sensitivity. Genetic tools, such as small interfering RNA (siRNA) can down-regulate molecular pathways such as HIF-1α and Nrf2 to promote ROS levels, leading to CP sensitivity. Considering the relationship between ROS and CP chemotherapy, and translating these findings to clinic can pave the way for effective treatment of cancer patients.

Molecular interactions of miR-338 during tumor progression and metastasis

Background

Cancer, as one of the main causes of human deaths, is currently a significant global health challenge. Since the majority of cancer-related deaths are associated with late diagnosis, it is necessary to develop minimally invasive early detection markers to manage and reduce mortality rates. MicroRNAs (miRNAs), as highly conserved non-coding RNAs, target the specific mRNAs which are involved in regulation of various fundamental cellular processes such as cell proliferation, death, and signaling pathways. MiRNAs can also be regulated by long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). They are highly stable in body fluids and have tumor-specific expression profiles, which suggest their suitability as efficient non-invasive diagnostic and prognostic tumor markers. Aberrant expression of miR-338 has been widely reported in different cancers. It regulates cell proliferation, migration, angiogenesis, and apoptosis in tumor cells.

Main body

In the present review, we have summarized all miR-338 interactions with other non-coding RNAs (ncRNAs) and associated signaling pathways to clarify the role of miR-338 during tumor progression.

Conclusions

It was concluded that miR-338 mainly functions as a tumor suppressor in different cancers. There were also significant associations between miR-338 and other ncRNAs in tumor cells. Moreover, miR-338 has a pivotal role during tumor progression using the regulation of WNT, MAPK, and PI3K/AKT signaling pathways. This review highlights miR-338 as a pivotal ncRNA in biology of tumor cells.

Employing siRNA tool and its delivery platforms in suppressing cisplatin resistance: Approaching to a new era of cancer chemotherapy

Although chemotherapy is a first option in treatment of cancer patients, drug resistance has led to its failure, requiring strategies to overcome it. Cancer cells are capable of switching among molecular pathways to ensure their proliferation and metastasis, leading to their resistance to chemotherapy. The molecular pathways and mechanisms that are responsible for cancer progression and growth, can be negatively affected for providing chemosensitivity. Small interfering RNA (siRNA) is a powerful tool extensively applied in cancer therapy in both pre-clinical (in vitro and in vivo) and clinical studies because of its potential in suppressing tumor-promoting factors. As such oncogene pathways account for cisplatin (CP) resistance, their targeting by siRNA plays an important role in reversing chemoresistance. In the present review, application of siRNA for suppressing CP resistance is discussed. The first priority of using siRNA is sensitizing cancer cells to CP-mediated apoptosis via down-regulating survivin, ATG7, Bcl-2, Bcl-xl, and XIAP. The cancer stem cell properties and related molecular pathways including ID1, Oct-4 and nanog are inhibited by siRNA in CP sensitivity. Cell cycle arrest and enhanced accumulation of CP in cancer cells can be obtained using siRNA. In overcoming siRNA challenges such as off-targeting feature and degradation, carriers including nanoparticles and biological carriers have been applied. These carriers are important in enhancing cellular accumulation of siRNA, elevating gene silencing efficacy and reversing CP resistance.

Non-Coding RNAs Participate in the Pathogenesis of Neuroblastoma

Neuroblastoma is one of the utmost frequent neoplasms during the first year of life. This pediatric cancer is believed to be originated during the embryonic life from the neural crest cells. Previous studies have detected several types of chromosomal aberrations in this tumor. More recent studies have emphasized on expression profiling of neuroblastoma samples to identify the dysregulated genes in this type of cancer. Non-coding RNAs are among the mostly dysregulated genes in this type of cancer. Such dysregulation has been associated with a number of chromosomal aberrations that are frequently detected in neuroblastoma. In this study, we explain the role of non-coding transcripts in the malignant transformation in neuroblastoma and their role as biomarkers for this pediatric cancer.

Potential Role of miRNAs in the Acquisition of Chemoresistance in Neuroblastoma

Neuroblastoma (NB) accounts for about 8–10% of pediatric cancers, and the main causes of death are the presence of metastases and the acquisition of chemoresistance. Metastatic NB is characterized by MYCN amplification that correlates with changes in the expression of miRNAs, which are small non-coding RNA sequences, playing a crucial role in NB development and chemoresistance. In the present study, miRNA expression was analyzed in two human MYCN-amplified NB cell lines, one sensitive (HTLA-230) and one resistant to Etoposide (ER-HTLA), by microarray and RT-qPCR techniques. These analyses showed that miRNA-15a, -16-1, -19b, -218, and -338 were down-regulated in ER-HTLA cells. In order to validate the presence of this down-regulation in vivo, the expression of these miRNAs was analyzed in primary tumors, metastases, and bone marrow of therapy responder and non-responder pediatric patients. Principal component analysis data showed that the expression of miRNA-19b, -218, and -338 influenced metastases, and that the expression levels of all miRNAs analyzed were higher in therapy responders in respect to non-responders. Collectively, these findings suggest that these miRNAs might be involved in the regulation of the drug response, and could be employed for therapeutic purposes.

New Evidence for P-gp-Mediated Export of Amyloid-β PEPTIDES in Molecular, Blood-Brain Barrier and Neuronal Models

Defective clearance mechanisms lead to the accumulation of amyloid-beta (Aβ) peptides in the Alzheimer’s brain. Though predominantly generated in neurons, little is known about how these hydrophobic, aggregation-prone, and tightly membrane-associated peptides exit into the extracellular space where they deposit and propagate neurotoxicity. The ability for P-glycoprotein (P-gp), an ATP-binding cassette (ABC) transporter, to export Aβ across the blood-brain barrier (BBB) has previously been reported. However, controversies surrounding the P-gp–Aβ interaction persist. Here, molecular data affirm that both Aβ₄₀ and Aβ₄₂ peptide isoforms directly interact with and are substrates of P-gp. This was reinforced ex vivo by the inhibition of Aβ₄₂ transport in brain capillaries from P-gp-knockout mice. Moreover, we explored whether P-gp could exert the same role in neurons. Comparison between non-neuronal CHO-APP and human neuroblastoma SK-N-SH cells revealed that P-gp is expressed and active in both cell types. Inhibiting P-gp activity using verapamil and nicardipine impaired Aβ₄₀ and Aβ₄₂ secretion from both cell types, as determined by ELISA. Collectively, these findings implicate P-gp in Aβ export from neurons, as well as across the BBB endothelium, and suggest that restoring or enhancing P-gp function could be a viable therapeutic approach for removing excess Aβ out of the brain in Alzheimer’s disease.

Silencing of long non-coding RNA DLX6-AS1 weakens neuroblastoma progression by the miR-513c-5p/PLK4 axis

Emerging evidence has demonstrated the crucial roles of long noncoding RNAs in human cancers, including neuroblastoma (NB). DLX6 antisense RNA 1 (DLX6-AS1) has been identified as an oncogenic driver in NB. However, the mechanisms of DLX6-AS1 in NB progression are not fully understood. Our data showed that DLX6-AS1 was significantly overexpressed in NB tissues and cells. Moreover, DLX6-AS1 silencing repressed NB cell viability, colony formation, migration, and invasion, and promoted cell cycle arrest and apoptosis in vitro, as well as decreased tumor growth in vivo. Mechanistically, DLX6-AS1 operated as a miR-513c-5p sponge. MiR-513c-5p mediated the regulation of DLX6-AS1 on NB cell malignant progression in vitro. PLK4 was a target of miR-513c-5p- and DLX6-AS1-controlled PLK4 expression via sponging miR-513c-5p. Furthermore, the suppressive effect of miR-513c-5p overexpression on NB cell malignant progression in vitro was reversed by PLK4 upregulation. Our findings identified a novel regulatory mechanism, the DLX6-AS1/miR-513c-5p/PLK4 axis, in NB progression, highlighting a strong rationale for developing DLX6-AS1 as a new target for NB management.