LINC00313 facilitates osteosarcoma carcinogenesis and metastasis through enhancing EZH2 mRNA stability and EZH2-mediated silence of PTEN expression

LINC00313 suppresses autophagy and promotes stemness of nasopharyngeal carcinoma cells through PTBP1/STIM1 axis

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a kind of malignant head and neck tumor with high mortality. lncRNAs are valuable diagnostic biomarkers and therapeutic targets for various tumors. This study investigated the effects and mechanism of LINC00313 in nasopharyngeal carcinoma.

METHODS

Cell Counting Kit-8 (CCK-8) and immunohistochemistry were used for assessing cell proliferation. The levels of autophagy-related proteins, and stem cell markers were detected. Immunofluorescence assay was used for LC3 detection. Methylated RNA Immunoprecipitation (meRIP) of LINC00313 in NPC cells was assessed. The localization of LINC00313 was verified by luorescence in situ hybridization (FIHS). The interaction between LINC00313 and the downstream targets were analyzed and confirmed by immunoprecipitation (RIP). Besides, the tumorigenesis roles of LINC00313 were confirmed in tumor growth mice model.

RESULTS

LINC00313 was increased in NPC tissues and cells. LINC00313 knockdown enhanced autophagy, and decreased stemness and cell viability of NPC cells through regulating STIM1. METTL3/IGF2BP1-mediated m6A modification promoted the stabilization and up-regulation of LINC00313. LINC00313 activated AKT/mTOR pathway in NPC cells through PTBP1/STIM1 axis. Moreover, LINC00313 promoted tumor growth and metastasis in xenograft model.

CONCLUSION

Upregulation of LINC00313 suppressed autophagy and promoted stemness of NPC cells through PTBP1/STIM1 axis.

Long noncoding RNA TUG1 promotes malignant progression of osteosarcoma by enhancing ZBTB7C expression

BACKGROUND

Dysregulation of long non-coding RNAs (lncRNAs) is an important component of tumorigenesis. Aberrant expression of lncRNA taurine upregulated gene 1 (lncTUG1) has been reported in various tumors; however, its precise role and key targets critically involved in osteosarcoma (OS) progression remain unclear.

METHODS

The expression profiles of lncRNAs and their regulated miRNAs related to OS progression were assessed by bioinformatics analysis and confirmed by qRT-PCR of OS cells. The miRNA targets were identified by transcriptome sequencing and verified by luciferase reporter and RNA pull-down assays. Several in vivo and in vitro approaches, including CCK8 assay, western blot, qRT-PCR, lentiviral transduction and OS cell xenograft mouse model were established to validate the effects of lncTUG1 regulation of miRNA and the downstream target genes on OS cell growth, apoptosis and progression.

RESULTS

We found that lncTUG1 and miR-26a-5p were inversely up or down-regulated in OS cells, and siRNA-mediated lncTUG1 knockdown reversed the miR-26a-5p down-regulation and suppressed proliferation and enhanced apoptosis of OS cells. Further, we identified that an oncoprotein ZBTB7C was also upregulated in OS cells that were subjected to lncTUG1/miR-26a-5p regulation. More importantly, ZBTB7C knockdown reduced the ZBTB7C upregulation and ZBTB7C overexpression diminished the anti-OS effects of lncTUG1 knockdown in the OS xenograft model.

CONCLUSIONS

Our data suggest that lncTUG1 acts as a miR-26a-5p sponge and promotes OS progression via up-regulating ZBTB7C, and targeting lncTUG1 might be an effective strategy to treat OS.

Revealing underlying regulatory mechanisms of LINC00313 in Osimertinib-resistant LUAD cells by ceRNA network analysis

BACKGROUND

Osimertinib, a third-generation epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI), is the preferred treatment for EGFR-mutated lung cancer. However, acquired resistance inevitably develops. While non-coding RNAs have been implicated in lung cancer through various functions, the molecular mechanisms responsible for osimertinib resistance remain incompletely elucidated.

METHODS

RNA-sequencing technology was employed to determine differentially expressed lncRNAs (DE-lncRNAs) and mRNAs (DE-mRNAs) between H1975 and H1975OR cell lines. Starbase 2.0 was utilized to predict DE-lncRNA and DE-mRNA interactions, constructing ceRNA networks. Subsequently, functional and pathway enrichment analysis were performed on target DE-mRNAs to identify pathways associated with osimertinib resistance. Key target DE-mRNAs were then selected as potential risk signatures for lung adenocarcinoma (LUAD) prognostic modeling using multivariate Cox regression analyses. The Quantitative Real-Time Polymerase Chain Reaction (qRT-PCR) and immunohistochemistry staining were used for result validation.

RESULTS

Functional analysis revealed that the identified DE-mRNAs primarily enriched in EGFR-TKI resistance pathways, especially in the PI3K/Akt signaling pathway, where their concerted actions may lead to osimertinib resistance. Specifically, upregulation of LINC00313 enhanced COL1A1 expression by acting as a miR-218-5p sponge, triggering an upstream response that activates the PI3K/Akt pathway, potentially contributing to osimertinib resistance. Furthermore, the expressions of LINC00313 and COL1A1 were validated by qRT-PCR, and the activation of the PI3K/Akt pathway was confirmed by immunohistochemistry staining.

CONCLUSIONS

Our results suggest that the LINC00313/miR-218-5p/COL1A1 axis potentially contributes to osimertinib resistance through the PI3K/Akt signaling pathway, providing novel insights into the molecular mechanisms underlying acquired osimertinib resistance in LUAD. Additionally, our study may aid in the identification of potential therapeutic targets for overcoming resistance to osimertinib.

Emerging roles of long non-coding RNAs in osteosarcoma

Osteosarcoma (OS) is a highly aggressive and lethal malignant bone tumor that primarily afflicts children, adolescents, and young adults. However, the molecular mechanisms underlying OS pathogenesis remain obscure. Mounting evidence implicates dysregulated long non-coding RNAs (lncRNAs) in tumorigenesis and progression. These lncRNAs play a pivotal role in modulating gene expression at diverse epigenetic, transcriptional, and post-transcriptional levels. Uncovering the roles of aberrant lncRNAs would provide new insights into OS pathogenesis and novel tools for its early diagnosis and treatment. In this review, we summarize the significance of lncRNAs in controlling signaling pathways implicated in OS development, including the Wnt/β-catenin, PI3K/AKT/mTOR, NF-κB, Notch, Hippo, and HIF-1α. Moreover, we discuss the multifaceted contributions of lncRNAs to drug resistance in OS, as well as their potential to serve as biomarkers and therapeutic targets. This review aims to encourage further research into lncRNA field and the development of more effective therapeutic strategies for patients with OS.

TGFβ-induced long non-coding RNA LINC00313 activates Wnt signaling and promotes cholangiocarcinoma

Cholangiocarcinoma is a devastating liver cancer characterized by high aggressiveness and therapy resistance, resulting in poor prognosis. Long non-coding RNAs and signals imposed by oncogenic pathways, such as transforming growth factor β (TGFβ), frequently contribute to cholangiocarcinogenesis. Here, we explore novel effectors of TGFβ signalling in cholangiocarcinoma. LINC00313 is identified as a novel TGFβ target gene. Gene expression and genome-wide chromatin accessibility profiling reveal that nuclear LINC00313 transcriptionally regulates genes involved in Wnt signalling, such as the transcriptional activator TCF7. LINC00313 gain-of-function enhances TCF/LEF-dependent transcription, promotes colony formation in vitro and accelerates tumour growth in vivo. Genes affected by LINC00313 over-expression in CCA tumours are associated with KRAS and TP53 mutations and reduce overall patient survival. Mechanistically, ACTL6A and BRG1, subunits of the SWI/SNF chromatin remodelling complex, interact with LINC00313 and affect TCF7 and SULF2 transcription. We propose a model whereby TGFβ induces LINC00313 in order to regulate the expression of hallmark Wnt pathway genes, in co-operation with SWI/SNF. By modulating key genes of the Wnt pathway, LINC00313 fine-tunes Wnt/TCF/LEF-dependent transcriptional responses and promotes cholangiocarcinogenesis.

RBM15-Mediated N6-Methyl Adenosine (m6A) Modification of EZH2 Drives the Epithelial-Mesenchymal Transition of Cervical Cancer

RBM15 functions as an oncogene in multi-type cancers. However, the reports on the roles of RBM15 in cervical cancer are limited. The purpose of this study was to investigate the potentials of RBM15 in cervical cancer. RT-qPCR was conducted to determine mRNA levels. Western was carried out to detect protein expression. CCK-8, colony formation and EdU assays were conducted to determine cell proliferation. Scratch and transwell assays were conducted to determine cell migration and invasion. MeRIP assay was conducted to determine N6-methyl adenosine (m6A) levels. Luciferase assay was conducted to verify the m6A sites of EZH2 and binding sites between EZH2 and promoter of FN1. ChIP assay was conducted to verify the interaction between EZH2 and FN1. The results showed that RBM15 was upregulated in cervical cancer patients and cells. Moreover, high levels of RBM15 predicted poor clinical outcomes. RBM15 knockdown inhibited the proliferation and epithelial-mesenchymal transition (EMT) of cervical cancer cells. RBM15 promoted the m6A modification of EZH2 as well as its protein translation. Additionally, EZH2 bound to the promoter of fibronectin 1 (FN1) and EZH2-FN1 axis is the cascade downstream of RBM15. Overexpressed EZH2 antagonized the effects of RBM15 knockdown and promoted the aggressiveness of cervical cancer cells. In summary, RBM15/EZH2/FN1 signaling cascade induces the proliferation and EMT of cervical cancer. Therefore, RBM15/EZH2/FN1 signaling may be a promising strategy for cervical cancer.

Extrachromosomal circular MiR-17-92 amplicon promotes HCC

BACKGROUND AND AIMS

Extrachromosomal circular DNAs (eccDNAs) are prevalent in cancer genomes and emerge as a class of crucial yet less characterized oncogenic drivers. However, the structure, composition, genome-wide frequency, and contribution of eccDNAs in HCC, one of the most fatal and prevalent cancers, remain unexplored. In this study, we provide a comprehensive characterization of eccDNAs in human HCC and demonstrate an oncogenic role of microRNA (miRNA)-17-92-containing eccDNAs in tumor progression.

APPROACH AND RESULTS

Using the circle-sequencing method, we identify and characterize more than 230,000 eccDNAs from 4 paired samples of HCC tumor and adjacent nontumor liver tissues. EccDNAs are highly enriched in HCC tumors, preferentially originate from certain chromosomal hotspots, and are correlated with differential gene expression. Particularly, a series of eccDNAs carrying the miRNA-17-92 cluster are validated by outward PCR and Sanger sequencing. Quantitative PCR analyses reveal that miRNA-17-92-containing eccDNAs, along with the expression of their corresponding miRNAs, are elevated in HCC tumors and associated with poor outcomes and the age of HCC patients. More intriguingly, exogenous expression of artificial DNA circles harboring the miR-17-92 cluster, which is synthesized by the ligase-assisted minicircle accumulation method, can significantly accelerate HCC cell proliferation and migration.

CONCLUSIONS

These findings delineate the genome-wide eccDNAs profiling of HCC and highlight the functional significance of miRNA-containing eccDNAs in tumorigenesis, providing insight into HCC pathogenesis and cancer therapy, as well as eccDNA and miRNA biology.

MicroRNA let-7c-5p Alleviates in Hepatocellular Carcinoma by Targeting Enhancer of Zeste Homolog 2: A Study Intersecting Bioinformatic Analysis and Validated Experiments

Enhancer of zeste homolog 2 (EZH2)gene has a prognostic role in hepatocellular carcinoma (HCC). This study aimed to identify the role of microRNAs (miRNAs) let-7c-5p by targeting EZH2 in HCC. We downloaded gene and miRNA RNA-seq data from The Cancer Genome Atlas (TCGA) database. Differences in EZH2 expression between different groups were analyzed and the association of EZH2 expression with HCC prognosis was detected using Cox regression analysis. The miRNA-EZH2-pathway network was constructed. Dual-luciferase reporter assay was performed to detect the hsa-let-7c-5p-EZH2. Cell proliferation, migration, invasion, and apoptosis were detected by CCK-8, Wound healing, Transwell, and Flow cytometry, respectively. RT-qPCR and Western blot were used to detect the expression of let-7c-5p and EZH2. EZH2 was upregulated in HCC tumors (P < 0.0001). Cox regression analysis showed that TCGA HCC patients with high EZH2 expression levels showed a short survival time [hazard ratio (HR) = 1.677, 95% confidence interval (CI) 1.316-2.137; P < 0.0001]. Seven miRNAs were negatively correlated with EZH2 expression and were significantly downregulated in HCC tumor samples (P < 0.0001), in which hsa-let-7c-5p was associated with prognosis in HCC (HR = 0.849 95% CI 0.739-0.975; P = 0.021). We identified 14 immune cells that showed significant differences in EZH2 high- and low-expression groups. Additionally, let-7c-5p inhibited HCC cell proliferation, migration, and invasion and reversed the promoted effects of EZH2 on HCC cell malignant characteristics. hsa-let-7c-5p-EZH2 significantly suppressed HCC malignant characteristics, which can be used for HCC prognosis.

LncRNA CALML3-AS1 modulated by m6A modification induces BTNL9 methylation to drive non-small-cell lung cancer progression

Non-small cell lung cancer (NSCLC) is a common and lethal malignancy. The carcinogenic roles of lncRNA CALML3 antisense RNA 1 (CALML3-AS1) have been documented. However, the function and potential mechanisms of CALML3-AS1 in the progression of NSCLC need to be further explored. The molecule expression was assessed by qRT-PCR and Western blot. The subcellular localization of CALML3-AS1 was observed by fluorescence in situ hybridization (FISH). The malignant behaviors of NSCLC cells were evaluated by CCK-8, colony formation, EdU, wound healing and transwell assays. In vivo xenograft tumor and liver metastatic models were established. The molecular mechanisms were investigated by RIP, RNA pull-down and ChIP assays. The methylation level was detected by MSP. Herein, we found that CALML3-AS1 was upregulated, while butyrophilin-like 9 (BTNL9) was downregulated in NSCLC. Functionally, CALML3-AS1 depletion repressed NSCLC cell malignant phenotypes, in vivo tumor growth, and liver metastasis. Mechanistically, AlkB homolog 5 (ALKBH5) enhanced CALML3-AS1 stability via N6-methyladenosine (m6A) demethylation, whereas m6A reader YTH domain-containing 2 (YTHDC2) destabilized CALML3-AS1. Moreover, CALML3-AS1 inhibited BTNL9 transcription and expression through the recruitment of Zeste homolog 2 (EZH2). Rescue experiments demonstrated that BTNL9 downregulation counteracted sh-CALML3-AS1-mediated antitumor effects on NSCLC. Taken together, CALML3-AS1 modulated by ALKBH5 and YTHDC2 in an m6A modification dependent manner drives NSCLC progression via epigenetically repressing BTNL9.

New emerging targets in osteosarcoma therapy: PTEN and PI3K/Akt crosstalk in carcinogenesis

Osteosarcoma (OS) is a malignant bone carcinoma that affects people in childhood and adulthood. The heterogeneous nature and chromosomal instability represent certain characteristics of OS cells. These cancer cells grow and migrate abnormally, making the prognosis undesirable for patients. Conventional and current treatments fail to completely eradicate tumor cells, so new therapeutics targeting genes may be considered. PI3K/Akt is a regulator of events such as growth, cell death, migration, and differentiation, and its expression changes during cancer progression. PTEN reduces PI3K/Akt expression, and its mutations and depletions have been reported in various tumors. Experimental evidence shows that there is upregulation of PI3K/Akt and downregulation of PTEN in OS. Increasing PTEN expression may suppress PI3K/Akt to minimize tumorigenesis. In addition, PI3K/Akt shows a positive association with growth, metastasis, EMT and metabolism of OS cells and inhibits apoptosis. Importantly, overexpression of PI3K/Akt causes drug resistance and radio-resistance and its level can be modulated by miRNAs, lncRNAs and circRNAs. Silencing PI3K/Akt by compounds and drugs can suppress OS. Here, we review in detail the function of the PTEN/PI3K/Akt in OS, revealing its biological function, function in tumor progression, resistance to therapy, and pharmacological significance.

Dissecting the role of lactate metabolism LncRNAs in the progression and immune microenvironment of osteosarcoma

BACKGROUND

The process of lactate metabolism has been proved to play a critical role in the progression of various cancers and to influence the immune microenvironment, but its potential role in osteosarcoma remains unclear.

METHODS

We have acquired transcriptomic and clinical data from 84 osteosarcoma samples and 70 normal bone samples from the TARGET and GTEx databases. We identified differentially expressed lactate metabolism-related LncRNAs (LRLs) in osteosarcoma and performed Cox regression and LASSO regression to establish LRLs prognostic signature (LRPS). The reliability of LRPS performance was examined by separate prognostic analysis, viability curves and receiver operating characteristic (ROC) curves. Furthermore, the effects of LRPS on the immune microenvironment of osteosarcoma were investigated, and the functions of the focal genes were experimentally validated.

RESULT

A total of 856 differentially expressed LRLs were identified and 5 of them were selected to construct LRPS, which was a better prognostic predictor for osteosarcoma compared with other published prognostic signatures (AUC up to 0.947 and 0.839 in the training and test groups, respectively, with adj-p<0.05 for KM curves). We found that LRPS significantly affected the immune infiltration of osteosarcoma, while RP11-472M19.2 significantly promoted the metastasis of osteosarcoma, which was well validated experimentally. Encouragingly, a number of sensitive drugs were identified for LRPS and RP11-472M19.2 high-risk groups.

CONCLUSION

Our study shows that lactate metabolism plays a crucial role in the development of osteosarcoma and has been well validated experimentally, providing extremely important insights into the clinical treatment and in-depth research of osteosarcoma.

Crosstalk between Noncoding RNAs and the Epigenetics Machinery in Pediatric Tumors and Their Microenvironment

According to the World Health Organization, every year, an estimated 400,000+ new cancer cases affect children under the age of 20 worldwide. Unlike adult cancers, pediatric cancers develop very early in life due to alterations in signaling pathways that regulate embryonic development, and environmental factors do not contribute much to cancer development. The highly organized complex microenvironment controlled by synchronized gene expression patterns plays an essential role in the embryonic stages of development. Dysregulated development can lead to tumor initiation and growth. The low mutational burden in pediatric tumors suggests the predominant role of epigenetic changes in driving the cancer phenotype. However, one more upstream layer of regulation driven by ncRNAs regulates gene expression and signaling pathways involved in the development. Deregulation of ncRNAs can alter the epigenetic machinery of a cell, affecting the transcription and translation profiles of gene regulatory networks required for cellular proliferation and differentiation during embryonic development. Therefore, it is essential to understand the role of ncRNAs in pediatric tumor development to accelerate translational research to discover new treatments for childhood cancers. This review focuses on the role of ncRNA in regulating the epigenetics of pediatric tumors and their tumor microenvironment, the impact of their deregulation on driving pediatric tumor progress, and their potential as effective therapeutic targets.

Bisphenol A interacts with DLGAP5 and regulates IL-6/JAK2/STAT3 signaling pathway to promote tumorigenesis and progression of osteosarcoma

OBJECTIVE

It has been suggested that Bisphenol A (BPA), a high-production-volume industrial chemical, can accelerate the development of various type of cancers. However, the effect of BPA on osteosarcoma and the underlying mechanisms are yet to be established. Therefore, in this study we tried to explore the carcinogenic effects of BPA on osteosarcoma and the underlying mechanism.

METHODS

SaOs-2 cancer cell line was used to treat with BPA at the doses of 0.1, 1, 10 μM DGLAP5 knockdown and overexpression methods were constructed by using adenovirus mediated transfection, and the functional analysis of DGLAP5 was investigated to evaluate the carcinogenic effect of BPA on osteosarcoma through DLGAP5. Xenograft and metastatic mouse model were used to evaluate in vivo experiments.

RESULTS

In this study, BPA at 10 μM promoted the proliferation, migration and invasion in vitro, and accelerate the progression and metastasis in vivo. Also, exposure to BPA was associated with poor survival of osteosarcoma in mice. In addition, we observed that BPA at 10 μM significantly increased the expression of DGLAP5 in osteosarcoma. Silencing DGLAP5 could reverse the effect of BPA on proliferation, migration and invasion. Mechanically, BPA promoted IL-6, JAK2, and STAT3 expression and promoted tumor progression in an IL-6-dependent manner through up-regulation of DLGAP5.

CONCLUSION

Our findings demonstrated that BPA could promote the proliferation, migration, invasion of osteosarcoma cells and related to poor survival in a mouse model. DLGAP5 is one of the most critical targets of BPA to act as a carcinogen through IL-6/JAK2/STAT3 signaling pathway.

Lead exposure promotes the inflammation via the circRNA-05280/miR-146a/IRAK1 axis in mammary gland

Lead, the most widely used heavy metal in industry, is detrimental to human health if exposed to living and occupational environment. Although several studies have been conducted on lead exposure, little has been reported on its harm to mammary gland and its mechanisms. In view of this, our study is the first to verify that lead exposure could promote apoptosis and inflammation in mouse mammary tissue (in vivo) and cow mammary epithelial cells (in vitro). After establishing a lead exposed mouse model, the expression profile of mammary gland tissue was constructed by high-throughput sequencing technology. In the profile, 917 differentially expressed genes were screened, of which IRAK1 was up-regulated by 4.33 times. Then, from qRT-PCR, Western blot and Luciferase report, IRAK1 was found to promote the release of inflammatory factors and tissue apoptosis and could be a specific target of miR-146a. On the other hand, double luciferase reporter system and qRT-PCR predicted the existence of a binding site between circRNA-05280 and miR-146a sequence. Experiments such as immunohistochemistry, apoptosis and EdU demonstrated that circRNA-05280 could promote not only cell apoptosis but also the expression level of inflammatory genes. Nevertheless, the function of miR-146a is opposite to that of circRNA-05280. Specifically, circRNA-05280 can regulate the level of apoptosis and inflammation of mammary gland by binding miR-146a and releasing the expression of miR-146a on target gene IRAK1. This study concludes that circRNA-05280/ miR-146a/ IRAK1 signaling pathway could mediate the mammary gland damage resulting from lead exposure. Accordingly, it sheds new light on further exploration of molecular mechanisms of mammary gland tissue damage caused by lead exposure, the risk assessment of lead, and the mechanism of lead mammary gland toxicity.

A Cohort Study to Evaluate the Efficacy and Value of CT Perfusion Imaging in Patients with Metastatic Osteosarcoma after Chemotherapy

Objective

A case-control study was conducted to explore the efficacy of cohort study and value of CT perfusion imaging in patients with metastatic osteosarcoma after chemotherapy.

Methods

Eighty patients with metastatic osteosarcoma treated in our hospital from March 2020 to December 2021 were divided into two groups. According to their different treatment methods, the chemotherapy+antiangiogenesis group had 36 cases and the chemotherapy group had 44 cases. All patients were scanned by 64-slice spiral CT before and after treatment. The differences of tumor volume and perfusion parameters before and after treatment were compared, and the correlation between perfusion parameters and tumor microvessel density (MVD) was analyzed. The receiver working curve (ROC curve) was used to evaluate the efficacy of the two groups after chemotherapy.

Results

Blood flow (BF), blood volume (BV), Pallak blood volume (PBV), and time to start (TTS) in the antitumor angiogenesis+chemotherapy group were significantly lower than those before treatment (P < 0.05). Microvessel density was positively correlated with PS, BF, BV, and PBV (P < 0.05). The reduction rate of BV and BF in the remission group after treatment was significantly higher than that in the nonremission group. When the BV and BF decline rates were 47.37% and 21.53% and the areas under the curve were 0.968 and 0.916, respectively, the diagnostic effect was the best. When the decrease rate of BV was 47.48% and the decrease rate of BF was 21.55%, the sensitivity was 94.72% and 89.56% and the specificity was 91.31% and 91.31%.

Conclusion

The reduction rate of BV and BF in CT perfusion imaging is of high value in evaluating the efficacy of radiotherapy and chemotherapy in patients with NSCLC and can provide more objective basis for observing the changes and judging the prognosis of osteosarcoma after treatment.