RNA Pull-down Assay Research Articles

ATRA-induced NEAT1 upregulation promotes autophagy during APL cell granulocytic differentiation

Aims Acute promyelocytic leukemia (APL) progresses quickly and often leads to early hemorrhagic death. Treatment with all-trans retinoic acid (ATRA) promotes differentiation of APL cells and clinical remission, making APL a potentially curable malignancy. Understanding how ATRA works may lead to new treatments for other types of leukemia. Long non-coding RNA NEAT1 has been implicated in the differentiation of APL cells. This study aims to elucidate the specific role of NEAT1 in the granulocytic differentiation of APL. Methods The influence of NEAT1 on autophagy and PML/RARα degradation was assessed using western blot assays. The impact of NEAT1 on the expression of autophagy-related genes was evaluated through quantitative real-time RT-PCR. Mechanistic insights into the role of NEAT1 in modulating autophagy were supported by RNA immunoprecipitation and RNA pulldown assays. Key findings Knockdown of NEAT1 suppressed autophagy and attenuated ATRA-induced PML/RARα degradation and granulocytic differentiation of APL cells. Subsequent screening of autophagy-related genes demonstrated that silencing NEAT1 impaired the ATRA-induced upregulation of ATG10 and ATG12. Mechanistic investigations revealed that the RNA-binding protein TAF15 interacted with NEAT1, synergistically stabilizing the mRNA of ATG10 and ATG12. Furthermore, knockdown of NEAT1 impaired the interactions between TAF15 and the mRNAs of ATG10 and ATG12, thereby compromising their mRNA stability. Significance Our study elucidates the critical role of NEAT1-mediated autophagy in the differentiation of APL cells and delineates the molecular mechanism by which upregulation of NEAT1 enhances autophagy. Specifically, NEAT1 binds to the RNA-binding protein TAF15, which in turn stabilizes the mRNA of both ATG10 and ATG12.

MyCAF-derived exosomal PWAR6 accelerates CRC liver metastasis via altering glutamine availability and NK cell function in the tumor microenvironment

BackgroundLiver metastasis from colorectal cancer (CRC) is a major clinical challenge that severely affects patient survival. myofibroblastic cancer-associated fibroblasts (myCAFs) are a major component of the CRC tumor microenvironment, where they contribute to tumor progression and metastasis through exosomes.MethodsSingle-cell analysis highlighted a notable increase in myCAFs in colorectal cancer liver metastases (CRLM). Exosomal sequencing identified PWAR6 as the most significantly elevated lncRNA in these metastatic tissues. In vivo and in vitro assays confirmed PWAR6's roles in CRC cell stemness, migration, and glutamine uptake. RNA pulldown, RIP, and Co-IP assays investigated the molecular mechanisms of the PWAR6/NRF2/SLC38A2 signaling axis in CRC progression, flow cytometry was used to assess NK cell activity and cytotoxicity.ResultsClinically, higher PWAR6 expression levels are strongly associated with increased 68Ga FAPI-PET/CT SUVmax values, particularly in CRLM patients, where expression significantly exceeds that of non-LM cases and normal colon tissues. Regression analysis and survival data further support PWAR6 as a negative prognostic marker, with elevated levels correlating with worse patient outcomes. Mechanistically, PWAR6 promotes immune evasion by inhibiting NRF2 degradation through competitive binding with Keap1, thereby upregulating SLC38A2 expression, which enhances glutamine uptake in CRC cells and depletes glutamine availability for NK cells.ConclusionmyCAFs derived exosomes PWAR6 represents a pivotal marker for CRC liver metastasis, and its targeted inhibition with ASO-PWAR6, in combination with FAPI treatment, effectively curtails metastasis in preclinical models, offering promising therapeutic potential for clinical management.Graphical abstract

A previously unidentified circRNA inhibits virus replication by regulating the miR-24-3p/KEAP1 axis.

Circular RNAs (circRNAs) exert diverse biological functions in different processes. However, the role of circRNAs during virus infection is mostly unknown. Herein, we explored the characteristics of host circRNAs using alphaherpesvirus pseudorabies virus (PRV) as a model. PRV infection upregulated the expression of circRNA circ29164, which does not encode a protein. RNA pulldown assays identified that circ29164 interacts with the microRNA ssc-miRNA-24-3p. Further analysis indicated that ssc-miR-24-3p targets the mRNA encoding kelch-like ECH-associated protein 1 (KEAP1), and circ29164 competitively binds to ssc-miR-24-3p to prevent it binding to Keap1. Apoptosis detection demonstrated that circ29164 or Keap1 overexpression, but not knockdown, induced caspase 3 activity and the release of cytochrome C from mitochondria, and inhibited PRV replication. Taken together, these data identified a previously undiscovered circRNA, circ29164, which inhibits PRV replication by competitively binding to ssc-24-3p to maintain KEAP1 levels.

A novel nuclear RNA HSD52 scaffolding NONO/SFPQ complex modulates DNA damage repair to facilitate temozolomide resistance.

Temozolomide (TMZ) is used in the treatment of glioblastoma (GBM). However, the primary obstacle remains the emergence of TMZ chemotherapy resistance. NONO and SFPQ are multifunctional nuclear proteins involved in genome stability and gene regulation. However, the specific role of NONO and SFPQ in TMZ resistance of GBM remains to be explored. RIP-chip and RNA microarray of TMZ-resistant and parental cells were performed for the gain of HSD52. The effects of HSD52 on TMZ resistance were investigated through in vitro assays, intracranial xenograft and GBM organoid models. The underlying mechanisms were explored by DNA methylation chip, RIP, RNA pulldown assays, among others. GBM clinical samples were rolled in to investigate the clinical significance of HSD52. We identified a novel non-coding RNA, HSD52, that was highly expressed in TMZ-resistant GBM and facilitated the interaction between NONO and SFPQ. H3 ubiquitination attenuation and reduced DNMT1 recruitment increased HSD52 transcription via DNA hypo-methylation. HSD52 formed an RNA duplex with UFL1 mRNA, thereby promoting NONO/SFPQ complex binding to UFL1 mRNA and enhancing its stability, and then contributed to TMZ resistance through activating ATM signaling pathway. In vivo xenograft and GBM organoid models showed significant repression in tumor growth after HSD52 knockout with TMZ treatment. In GBM clinical samples, HSD52 was responsible for the malignant progression and TMZ resistance. Our results revealed that HSD52 could serve as a promising therapeutic target to overcome TMZ resistance, improving the clinical efficacy of TMZ chemotherapy in GBM.

Circular RNA circ_0004630 promotes malignancy and glycolysis of nonsmall cell lung cancer by sponging microRNA-1208 and regulating leucine-rich repeat kinase 2 expression.

Emerging evidence has discovered that circular RNAs play important regulators of nonsmall cell lung cancer (NSCLC), but the role and potential molecular mechanism of hsa_circ_100549 (circ_0004630) involved in NSCLC is poorly defined. In this study, circ_0004630, microRNA-1208 (miR-1208), and leucine-rich repeat kinase 2 (LRRK2) expression were detected using real-time quantitative polymerase chain reaction. Cell proliferation, colony formation, apoptosis, and invasion were assessed using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine, colony formation, flow cytometry, and transwell assays. Protein levels of glucose transporter 1, Hexokinase 2, and LRRK2 were detected using western blot assay. Glucose consumption, lactate production, and adenosine triphosphatecontent were assessed using the corresponding kits. After predicting via bioinformatics software Circinteractome and Targetscan, the binding between miR-1208 and circ_0004630 or LRRK2 was verified by a dual-luciferase reporter, RNA immunoprecipitation, and RNA pull-down assay. The xenograft tumor model analyzed the biological role circ_000460 on tumor growth in vivo. It was found that circ_0004630 and LRRK2 were increased, and miR-1208 was low expression in NSCLC tissues and cells. Functionally, the downregulation of circ_0004630 inhibited NSCLC cell proliferation, invasion, glycolysis, and accelerated apoptosis in vitro. In mechanism, circ_0004630 might work as a sponge of miR-1208 to modulate LRRK2 expression. In addition, DUXAP8 deficiency cured neuroblastoma tumor growth in vivo. In conclusion, circ_0004630 knockdown might suppress NSCLC cell proliferation, metastasis, and glycolysis partly by the miR-1208/LRRK2 axis. Our findings hinted at an important theoretical basis for further elucidating the pathogenesis of NSCLC and targeted therapy.

Long Noncoding RNA LINC02453 Inhibits HIV-1 Replication by Binding With SEC13 to Regulate the Viral Productive Cycle.

Emerging evidence underscores the pivotal role of long noncoding RNAs (lncRNAs) as crucial regulators within the HIV life cycle. However, the precise functions and detailed mechanisms by which lncRNAs operate in HIV-1 highly exposed but persistently seronegative (HESN) individuals remain currently unknown. Through RNA sequencing analysis of the HESN individual and the matched control, we identified potential lncRNAs. Then, we conducted validation experiments at the population level, while cellular models of HIV-1 infection were constructed for functional experimental investigations in vitro. Subcellular localization of the identified lncRNA was determined, followed by an exploration of the specific regulatory mechanism underlying HIV resistance through some experiments, such as RNA pull-down, western blot and Hirt assays. LncRNA LINC02453 is highly expressed in HESN. Moreover, LINC02453 is identified as a novel lncRNA associated with heightened resistance to HIV-1. LINC02453 is predominantly localized in the nucleus and binds to SEC13, a component of the nuclear pore complex, leading to the inhibition of HIV-1 replication by regulating key processes such as late reverse transcription, nuclear import, and DNA integration. Our findings suggest that LINC02453 may serve as a prospective target for the development of innovative anti-HIV therapeutics.

Long Non-Coding RNA SNHG3 Promotes the Progression of Cholangiocarcinoma by Regulating the miR-151a-3p/STAT5a Axis.

Studies have shown the significance of long non-coding RNAs (lncRNAs) in the development of malignant tumors, including cholangiocarcinoma (CCA). However, the molecular mechanisms through which the lncRNA SNHG3 contributes to CCA development remain unknown. Therefore, the purpose of this work was to investigate SNHG3's role and possible processes in CCA. CCK-8, TUNEL, wound healing, and transwell assays were performed to evaluate the viability, apoptosis, migration, and invasion of CCA cells, respectively. Dual-luciferase reporter and RNA pull-down assays were conducted to verify the relationship between SNHG3 and miR-151a-3p and that between STAT5a and miR-151a-3p. SNHG3 and STAT5a were considerably upregulated and miR-151a-3p was downregulated in CCA tissues and cells. SNHG3 knockdown suppressed the proliferation, apoptosis, migration, and invasive ability of HUCC-T1 cells. Mechanistically, SNHG3 directly targeted miR-151a-3p to promote the development of CCA. Treatment with a miR-151a-3p inhibitor reversed the effects of SNHG3 knockdown on the aggressive behavior of HUCC-T1 cells. Furthermore, STAT5a knockdown counteracted the effects of inhibition of SNHG3 and miR-151a-3p on the aggressive behavior of CAA. SNHG3 promotes CCA progression via the miR-151a-3p/STAT5a axis, providing novel insights into the clinical treatment of CCA.

CircUBE2G1 interacts with hnRNPU to promote VEGF-C-mediated lymph node metastasis of lung adenocarcinoma.

Patients with lymph node(LN)metastasis-positive Lung adenocarcinoma(LUAD)suffer from a significantly reduced five-year survival rate. Increasing evidence indicates circular RNAs(circRNAs)play crucial roles in regulating cancer progression. However, the specific regulatory mechanisms of circRNAs in the LN metastasis of LUAD have not been fully explored. GEO datasets and sequence analysis were applied for the identification of differentially expressed circRNAs between LUAD tissues and adjacent normal tissues. In vitro and in vivo experiments were performed to evaluate the function of circUBE2G1. The interaction between circUBE2G1 and VEGF-C was determined by RNA pulldown, ChIP, ChIRP and luciferase assays. In this study, we identified a novel circRNA, circUBE2G1 (hsa_circ_0041555), which is upregulated in LUAD and positively correlated with LN metastasis in patients with LUAD. Functionally, overexpression of circUBE2G1 promotes lymphangiogenesis and LN metastasis of LUAD both in vitro and in vivo. Mechanistically, circUBE2G1 activates the transcription of vascular endothelial growth factor C (VEGF-C) by recruiting hnRNPU to enhance H3K27ac on the VEGF-C promoter, thereby facilitating lymphangiogenesis and LN metastasis in LUAD. Our findings offer new insights into the mechanisms behind circRNA-mediated LN metastasis in LUAD and suggest that circUBE2G1 may serve as a potential therapeutic target for LN metastasis in LUAD.

EIF4A3-induced hsa_circ_0127071 promotes human glomerular mesangial cells senescence via JAK2/STAT5 signaling pathway.

Circular RNAs (circRNAs) have garnered attention for their potential involvement in the regulation of cellular aging processes. Exploring the role and mechanism of circRNAs in cellular senescence may help to identify new anti-aging therapeutic targets. In the present study, we investigated the role and regulatory mechanism of hsa_circ_0127071 in renal aging. We employed high-throughput sequencing to assess circRNA expression differences in kidney tissues from young and old groups. qRT-PCR confirmed that the expression of hsa_circ_0127071 in kidney tissue of the old group was significantly higher than that of the young group. Cellular senescence was evaluated using SA-β-Gal staining and Masson's trichrome staining. Using RNA Immunoprecipitation (RIP), RNA Pull-Down Assay (RNA pull down), and Western Blot (WB) to study the interaction between hsa_circ_0127071 and aging related pathway proteins. In this study, we found that the expression of hsa_circ_0127071 in kidney tissue of the old group was significantly higher than that of the young group. Silencing of EIF4A3, a protein involved in the JAK2/STAT5 signaling pathway, was found to delay the aging process. On the basis of silencing EIF4A3 expression, the JAK2/STAT5 signaling pathway was activated by Erythropoietin (EPO) processing, and the senescence of Human glomerular mesangial cells(HGMCs) increased. After treatment with Losartan (LOS), the activity of JAK2/STAT5 pathway was decreased and the aging process of HGMCs was delayed. Our findings demonstrate that hsa_circ_0127071 promotes renal aging through the EIF4A3/JAK2/STAT5 signaling axis, highlighting a novel potential therapeutic target for the management of renal aging and associated disorders.

Mbnl1-mediated alternative splicing of circMlxipl regulates Rbbp6-involved ChREBP turnover to inhibit lipotoxicity-induced β-cell damage

BackgroundDiabetes, a global epidemic, is the leading cause of mortality globally. The aim of this study is to get better understanding of pathophysiology of diabetes.MethodsPalmitic acid (PA)-treated β-cells, db/db mice and high fat diet (HFD)-fed mouse model of type 2 diabetes were established. H&E was used to assess the histological changes of pancreas. IHC, FISH, western blot or qRT-PCR was employed to detect the expression of key molecules in primary islets or lipotoxic β-cells. Cell behaviors were detected by MTT, EdU incorporation assay, TUNEL assay and glucose-induced insulin secretion (GSIS). The associations among circMlxipl, Mbnl1 and Rbbp6 were validated by RIP and RNA pull-down assays, and the direct binding between Hdac3 and Mbnl1 promoter was examined by ChIP and luciferase assays. Co-IP was employed to assess the interaction between ChREBP and Rbbp6, as well as the ubiquitination of ChREBP.ResultsHdac3 and ChREBP were upregulated, but Mbnl1 and circMlxipl were downregulated in islets from diabetic mice and lipotoxic β-cells. Mbnl1 overexpression protected against PA-induced impairments in lipotoxic β-cells through modulating back-splicing of circMlxipl and suppressing ChREBP. Hdac3 served as a transcriptional repressor of Mbnl1, and it was implicated in circMlxipl-mediated protection via regulating ChREBP expression in lipotoxic β-cells. Lack of circMlxipl inhibited Rbbp6-mediated ubiquitin-proteasomal degradation of ChREBP in lipotoxic β-cells. In vivo studies revealed that Hdac3 knockdown or Mbnl1 overexpression alleviated diabetes symptoms through circMlxipl-regulated ChREBP in diabetic mice.ConclusionMbnl1-mediated alternative splicing of circMlxipl regulates Rbbp6-involved ChREBP turnover to inhibit lipotoxicity-induced β-cell damage.

Hsa_circ_0072732 enhances sunitinib resistance of renal cell carcinoma by inhibiting ferroptosis

BackgroundRenal cell carcinoma (RCC) is one of the most diagnosed urological malignancies with high mortality and increasing incidence. What’s more, the sunitinib resistance undoubtedly increased the difficulties in RCC therapy. Circular RNAs (circRNAs) are a newly found type of non-coding RNAs with a special circular structure, and are found to participate in the occurrence development, chemoresistance, and prognosis of cancers. Ferroptosis regulates disease progression mainly via polyunsaturated fatty acid metabolism and glutamine catabolic pathways. The mechanism of circRNAs contributed to sunitinib resistance through ferroptosis has not been elucidated clearly.Materials and methodsIn our research, we identified a novel circRNA Hsa_circ_0072732 from circRNA datasets (GSE108735 and GSE100186). RNase R and Actinomycin D assays were used to detect the loop structure and stability of circRNAs. qRT-PCR and western blot were used for the detection of RNA and protein levels. CCK8 assays were used to detect proliferation and cell viability. Lipid peroxidation (MDA), and reactive oxygen species (ROS) were detected by indicted kits. Dual-luciferase reporter and RNA pull-down assays were used to detect the RNA interactions.ResultsOur results showed that Hsa_circ_0072732 was highly expressed in RCC cells. Further investigations showed that the silence of Hsa_circ_0072732 could increase RCC sensitivity to sunitinib. Hsa_circ_0072732 contributed to sunitinib chemoresistance by impairing ferroptosis. Hsa_circ_0072732 exerts its function mainly by acting as sponges for miR-548b-3p and regulating the expression SLC7A11. Our research suggests that ferroptosis is involved in sunitinib resistance, and targeting ferroptosis is a promising way for RCC treatment.ConclusionOur research suggests Hsa_circ_0072732 enhanced renal cell carcinoma sunitinib resistance by inhibiting ferroptosis through miR-548b-3p/SLC7A11.

Transcriptional and post-transcriptional regulation of CARMN and its anti-tumor function in cervical cancer through autophagic flux blockade and MAPK cascade inhibition

BackgroundLncRNAs play essential roles in multiple tumors. However, research on genome-wide lncRNA alterations and their functions in cervical cancer (CC) is limited. This study aims to explore key lncRNAs in CC progression and uncover the molecular mechanisms involved in the development of CC.MethodsIn this study, we analyzed 30 tissues from CC, cervical intraepithelial neoplasia (CIN), and normal (NOR) using transcriptome sequencing and weighted gene co-expression network analysis to establish gene modules related to the NOR-CIN-CC transition. Machine learning diagnostic models were employed to investigate the role of lncRNAs in this transition. Molecular biological experiments were conducted to elucidate the potential mechanisms of CARMN in CC, with a particular focus on its transcriptional and post-transcriptional regulation of abnormal expression in CC.ResultsCARMN was identified as a hub gene in two modules significantly associated with the NOR-CIN-CC transition. Analysis using ten machine learning models confirmed its critical role in this progression. The results of RNA-seq, qPCR and RNAScope performed in another cohort of 83 cervical tissues all showed that CARMN was significantly downregulated in CC. CARMN significantly enhanced the interaction between Keap1 and Nrf2, leading to increased ROS levels. The elevated ROS levels suppressed the Akt/mTOR signaling pathway, leading to autophagy arrest via autophagic flux blockade. Additionally, CARMN interacted with TFAP2α to repress MAPK13 transcription, further inhibiting the MAPK cascade. A promoter SNP (rs12517403) was found to increase CC risk (OR = 1.34, 95% CI = 1.11–1.61) and reduce CARMN expression by decreasing SP1 binding. Furthermore, the RNA binding proteins that could modulate CARMN RNA stability were also determined using RNA-pulldown assay. The results demonstrated that YBX1, a component of the coding region instability determinant (CRD)-mediated mRNA stabilization complex, promoted CARMN RNA stability. DHX9, another component of complex, acted as a scaffold to bridge YBX1 and CARMN.ConclusionsCARMN exerts an anti-cancer effect in CC progression by inhibiting the Akt-mTOR and MAPK signaling pathways. rs12517403 and the YBX1/DHX9 complex are key mechanisms influencing its transcription and stability in CC cells. CARMN represents a promising biomarker for CC diagnosis and therapeutic target.

Abstract B019: Androgen receptor-regulated lncRNA PRCAT71 promotes AR signaling through the interaction with RBPs in prostate cancer

Abstract Prostate cancer (PCa) is the second leading cause of cancer death in American men. PCa patients usually receive androgen deprivation therapy but eventually, they will relapse and tumors become castration-resistant PCa (CRPC) without effective treatments, highlighting the urgent need to develop better therapeutics to target advanced PCa. The main mechanism identified leading to castration resistance is aberrant androgen receptor (AR) reactivation, including AR overexpression. Approximately 80% of CRPC patients have a marked increase in AR mRNA and protein expression. Emerging evidence suggests genomic and transcriptomic changes insufficiently predict biology and mRNA and protein expression levels frequently do not correlate. Posttranscriptional regulation of AR mRNA can lead to AR overexpression. RNA binding proteins (RBPs) and non-coding RNAs (ncRNAs), such as microRNAs, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), can control gene expression via direct binding to mRNAs and regulating mRNA processing, modification, and translation. Here in this study, we identified a novel PCa-specific lncRNA, PRCAT71, which is higher expressed in prostate tumor tissues than in benign tissues. Silencing PRCAT71 suppressed the cancerous properties of PCa cells, and reduced AR mRNA and protein expression levels, leading to inhibited AR signaling. We further uncovered that PRCAT71 formed an RNA-RNA duplex with AR mRNA, which enhanced the stability of AR mRNA. RNA pulldown assay identified PRCAT71- interacted RBPs. Silencing PRCAT71 reduced the interaction between key RBPs and AR mRNA, which is related to PRCAT71 regulating AR mRNA stability. Interestingly, PRCAT71 is transcriptionally regulated by AR-driven enhancers, thus forming a positive regulatory loop between AR and PRCAT71 in PCa. The high expression of PRCAT71 and key RBPs in PCa tumors are positively correlated with PSA level, AR activity and indicate worse patient overall survival and metastasis-free survival. Our study revealed a novel regulatory mechanism by which lncRNA PRCAT71 enhances the interaction of key RBPs with AR mRNA, stabilizes AR mRNA and promotes AR expression and PCa progression. Targeting PRCAT71-RBPs is a promising approach to treating CRPC. Citation Format: Yongyong Yang, Ting-You Wang, Qianru Li, Adam B Weiner, Jiawen Lu, Yanan Ren, Qingxiang Guo, Chaehyun Yum, Qi Liu, Rui Wang, Zhe Ji, Tamara L Lotan, Edward M Schaeffer, Rendong Yang, Qi Cao. Androgen receptor-regulated lncRNA PRCAT71 promotes AR signaling through the interaction with RBPs in prostate cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B019.

M6A-modified circCacna1c regulates necroptosis and ischemic myocardial injury by inhibiting Hnrnpf entry into the nucleus

BackgroundCircular RNAs (circRNAs) are differentially expressed in various cardiovascular diseases, including myocardial infarction (MI) injury. However, their functional role in necroptosis-induced loss of cardiomyocytes remains unclear. We identified a cardiac necroptosis-associated circRNA transcribed from the Cacna1c gene (circCacna1c) to investigate the involvement of circRNAs in cardiomyocyte necroptosis.MethodsTo investigate the role of circCacna1c during oxidative stress, H9c2 cells and neonatal rat cardiomyocytes were treated with hydrogen peroxide (H2O2) to induce reactive oxygen species (ROS)-induced cardiomyocyte death. The N6-methyladenosine (m6A) modification level of circCacna1c was determined by methylated RNA immunoprecipitation quantitative polymerase chain reaction (MeRIP–qPCR) analysis. Additionally, an RNA pull-down assay was performed to identify interacting proteins of circCacna1c in cardiomyocytes, and the regulatory role of circCacna1c in target protein expression was tested using a western blotting assay. Furthermore, the MI mouse model was constructed to analyze the effect of circCacna1c on heart function and cardiomyocyte necroptosis.ResultsThe expression of circCacna1c was found to be reduced in cardiomyocytes exposed to oxidative stress and in mouse hearts injured by MI. Overexpression of circCacna1c inhibited necroptosis of cardiomyocytes induced by hydrogen peroxide and MI injury, resulting in a significant reduction in myocardial infarction size and improved cardiac function. Mechanistically, circCacna1c directly interacts with heterogeneous nuclear ribonucleoprotein F (Hnrnpf) in the cytoplasm, preventing its nuclear translocation and leading to reduced Hnrnpf levels within the nucleus. This subsequently suppresses Hnrnpf-dependent receptor-interacting protein kinase 1 (RIPK1) expression. Furthermore, fat mass and obesity-associated protein (FTO) mediates demethylation of m6A modification on circCacna1c during necrosis and facilitates degradation of circCacna1c.ConclusionOur study demonstrates that circCacna1c can improve cardiac function following MI-induced heart injury by inhibiting the Hnrnpf/RIPK1-mediated cardiomyocyte necroptosis. Therefore, the FTO/circCacna1c/Hnrnpf/RIPK1 axis holds great potential as an effective target for attenuating cardiac injury caused by necroptosis in ischemic heart disease.Graphical

Activation of Hedgehog pathway by circEEF2/miR-625-5p/TRPM2 axis promotes prostate cancer cell proliferation through mitochondrial stress.

The purpose of this study was to identify the role played by circEEF2 (has-circ-0048559) in prostate cancer (PCa) development and to determine the potential mechanism involved. circEEF2, miR-625-5p, and the transient receptor potential M2 channel protein (TRPM2) were determined using RT-qPCR in PCa. Cell proliferation was determined by CCK-8 assay and colony formation assay, whereas migration and invasion were assessed by Transwell assay, and apoptosis was evaluated by flow cytometry after annexin V-FITC and propidium iodide staining. The interactions between circEEF2 and miRNAs were investigated through the Circular RNA Interactome database, and the downstream targets of miR-625-5p were forecasted using TargetScan. The interaction was confirmed using both the dual luciferase reporter gene assay and RNA pull-down assay. TRPM2, Hedgehog signaling pathway proteins (GLI1 and GLI2), ubiquinone oxidase subunit B8, and cytochrome C oxidase subunit IV (COX4) were analyzed by protein blotting. JC-1 fluorescence detection was applied for mitochondrial membrane potential changes, fluorescent probe assay for intracellular ROS levels, and immunofluorescence staining for γ-H2AX expression. The role of circEEF2 in PCa tumor growth was tested by xenograft experiments. CircEEF2 expression was upregulated in PCa (p<0.05). Cells of PCa were inhibited in proliferation, migration, invasion, and enhanced in apoptosis by depleting circEEF2 (p<0.05). circEEF2 directly targeted adsorbed miR-625-5p. TRPM2 bound to miR-625-5p. Upregulating TRPM2 likewise reversed the therapeutic effect of depleting circEEF2 on cancer development in PCa cells. circEEF2 activated the Hedgehog pathway through the miR-625-5p/TRPM2 axis, promotes mitochondrial stress, and promotes PCa development in vivo. circEEF2 upregulates mitochondrial stress to promote PCa by activating the Hedgehog pathway through the miR-625-5p/TRPM2 axis.

The miR-31b targets arylsulfatase B to regulate the ovarian development of Bactrocera dorsalis.

Reproduction is the basis of insect population growth and evolution, and encompasses ovarian development, reproductive behavior, and fecundity. Bactrocera dorsalis is a globally significant agricultural pest that is subject to quarantine, with mated females that can lay over 3000 eggs. The post-transcriptional regulation of ovarian development remains unclear. Here, miR-31b is shown to be involved in regulating Bactrocera dorsalis ovarian development. CRISPR/Cas9 was used to generate miR-31b loss-of-function mutations in Bactrocera dorsalis. The removal of miR-31b resulted in severely impaired ovarian development in adults, with phenotypes that included dramatically reduced egg production and hatching rates. The relationship between miR-31b and its target gene arylsulfatase B (ARSB) was subsequently identified using the methods of bioinformatics, transcriptomic sequencing, quantitative polymerase chain reaction (qPCR), RNA pull-down and dual-luciferase reporter assay. Finally, miR-31b was confirmed to bind the target gene arylsulfatase B to affect metabolism and thereby further hindered ovarian development of Bactrocera dorsalis. Overall, these results provide new insights into molecular mechanisms at the post-transcriptional level in regulating ovarian development and insect reproduction, consequently providing potential targets to control arthropod pests through the reproductive strategy. © 2024 Society of Chemical Industry.

LINC01764 promotes colorectal cancer cells proliferation, metastasis, and 5-fluorouracil resistance by regulating glucose and glutamine metabolism via promoting c-MYC translation.

Few biomarkers are available for predicting chemotherapeutic response and prognosis in colorectal cancer (CRC). Long-noncoding RNAs (lncRNAs) are essential for CRC development and growth. Therefore, studying lncRNAs may reveal potential predictors of chemotherapy response and prognosis in CRC. LINC01764 was analyzed using datasets from Fudan University Shanghai Cancer Center's advanced CRC patients' RNA-seq and The Cancer Genome Atlas datasets. Gene set enrichment analysis was employed to detect related pathways. Cotransfection experiments, RNA pulldown assays, RNA-binding protein immunoprecipitation, protein synthesis activity, and dual-luciferase reporter assays were performed to determine interactions among LINC01764, hnRNPK, and c-MYC. High LINC01764 expression correlates with metastasis, a poor response to FOLFOX/XELOX chemotherapy, and a poor prognosis in CRC. LINC01764 enhance glycolysis and glutamine metabolism to promote CRC cells proliferation, metastasis, and 5-fluorouracil (5-FU) resistance. LINC01764 specifically binds to hnRNPK, facilitating its interaction with c-MYC mRNA and promoting internal ribosome entry site (IRES)-dependent translation of c-MYC, thereby exerting oncogenic effects. LINC01764 induced 5-FU chemoresistance by upregulating the c-MYC, glucose, and glutamine metabolism pathways, which downregulated UPP1, crucial for activating 5-FU. Conclusively, LINC01764 promotes CRC progression and 5-FU resistance through hnRNPK-mediated-c-MYC IRES-dependent translational regulation, which suggests its potential as a predictor of CRC chemotherapy response and prognosis.

Overcoming multi-drug resistance in SCLC: a synergistic approach with venetoclax and hydroxychloroquine targeting the lncRNA LYPLAL1-DT/BCL2/BECN1 pathway

BackgroundSmall cell lung cancer (SCLC) stands as one of the most lethal malignancies, characterized by a grim diagnosis and prognosis. The emergence of multi-drug resistance poses a significant hurdle to effective therapy. Although previous studies have implicated the long noncoding RNA LYPLAL1-DT in the tumorigenesis of SCLC, the precise role of the highly expressed LYPLAL1-DT in SCLC chemoresistance and the underlying mechanism remain inadequately understood.MethodscDDP-, VP-16- and PTX-resistant SCLC cells lines were established. The viabilities of SCLC cells were assessed by CCK-8 assay in vitro and xenograft tumor formation assay in vivo. Apoptosis was evaluated by FACS, Western blot and JC-1 fluorescence staining, while autophagy was explored via autophagic flux detection under confocal microscopy and autophagic vacuole investigation under transmission electron microscopy (TEM). The functional role and mechanism of LYPLAL1-DT were further investigated by gain- and loss-of-function assays in vitro. Furthermore, the therapeutic efficacy of the combination of venetoclax and HCQ with cDDP, VP-16 or PTX was evaluated by cell line, cell-derived xenograft (CDX) and patient-derived xenograft (PDX) mice model.ResultsOur findings revealed that LYPLAL1-DT is upregulated in chemoresistant SCLC cell lines. Gain- and loss-of-function assays demonstrated that LYPLAL1-DT impairs sensitivity to cDDP, VP-16, or PTX both in vitro and in vivo. Overexpression of LYPLAL1-DT significantly enhanced autophagy and inhibited apoptosis in SCLC cells. Further analyses, including RIP and RNA pull-down assays, revealed that LYPLAL1-DT promotes the expression of BCL2 by sponging miR-204-5p and is implicated in the assembly of the autophagy-specific complex (BECN1/PtdIns3K complex). Combining venetoclax and HCQ with cDDP, VP-16, or PTX effectively mitigated chemoresistance in SCLC cells and suppressed tumor growth in CDX and PDX models without inducing obvious toxic effects.ConclusionsOur findings demonstrate that upregulation of LYPLAL1-DT sequesters apoptosis through the LYPLAL1-DT/miR-204-5p/BCL2 axis and promotes autophagy by facilitating the assembly of the BECN1/PtdIns3K complex, thereby mediating multi-drug resistance of SCLC. The triple combination of venetoclax, HCQ, in conjunction with cDDP, VP-16 or PTX overcomes refractory SCLC, shedding light on a potential therapeutic target for combating SCLC chemoresistance.

Glycolysis regulated exosomal LINC01214 inhibited CD8+ T cell function and induced anti-PD1 resistance in melanoma via modulating miR-4492/PPP1R11 axis

BackgroundLong non-coding RNAs (lncRNAs) can be incorporated into exosomes to mediate the intercellular communication, regulating the occurrence, development, and immunosuppression of cancers. T cell dysfunction has been a hallmark of many cancers, including melanoma, which enables cancer cells escape from host immune surveillance. However, the molecular mechanism of exosome-transmitted lncRNAs in CD8+ T cell dysfunction in melanoma remains largely unclear. MethodThe expression of circulating LINC01214 (cirLINC01214) was detected by quantitative real-time polymerase chain reaction (RT-qPCR). Exosomes were isolation from the culture medium and plasma of melanoma patients via ultracentrifugation and characterized by transmission electronic microscopy. The regulation of exosomal LINC01214 on CD8+ T cell function was determined by ELISA. The molecular mechanism of exosomal LINC01214 in CD8+ T cells were assessed by the RNA immunoprecipitation and pull-down assay. A mouse model with reconstituted human immune system was used to explore the role of exosomal LINC01214 in the resistance to anti-PD1 therapy. ResultsLINC01214 was highly expressed in melanoma tissues compared with matched adjacent normal tissues. Increased levels of circulating LINC01214 (cirLINC01214) was observed in melanoma patient plasma and correlated with poor PD-1 immunotherapy response. The cirLINC01214 was predominantly released by melanoma cells in an exosome manner. Melanoma cell-derived exosomal LINC01214 inhibits the production of IFN-γ, TNF-α, Granzyme-B and Perforin by CD8+ T cells. Further mechanism study found that cirLINC01214 delivered by exosomes suppressed CD8+ T cell function by up-regulating the expression of Protein Phosphatase 1 Regulatory Inhibitor Subunit 11 (PPP1R11) through sponging miR-4492. CirLINC01214 conferred resistance to PD-1 immunotherapy in melanoma xenograft mouse model. Melanoma patients with poor prognosis after PD-1 treatment carried high levels of exosomal LINC01214. Additionally, the secretion of exosomal cirLINC01214 was enhanced by the Warburg effect, which was consistent with the reprogrammed glucose metabolism of melanoma. ConclusionsOur results demonstrated that exosomal LINC01214 released by melanoma cells promoted immunotherapy resistance by inducing CD8+ T cell dysfunction via the miR-4492/PPP1R11 regulatory loop. Targeting cirLINC01214 might be a potential therapeutic strategy to enhance the outcome of immunotherapy in melanoma.

Ginsenoside Rg3 activates the immune function of CD8+ T cells via circFOXP1-miR-4477a-PD-L1 axis to induce ferroptosis in gallbladder cancer.

Gallbladder cancer (GBC) is the most common and leading cause of cancer-associated mortality among biliary tract carcinomas worldwide and there is no specific drug for treatment. Activation of CD8+ T cell immune activity is one of the strategies to improve GBC treatment. This study is aimed to investigate the role of Ginsenoside Rg3 on CD8+ T cell activation and pathogenesis of GBC. In GBC cells, Rg3 administration led to the significant reduction of circFOXP1 and PD-L1 as measured by Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blotting. Mechanistically, circFOXP1 acted as the sponge of miR-4477a to regulate PD-L1 expression as demonstrated by RNA pull-down assay and dual luciferase reporter assay. Rg3 treatment enhanced the activity of CD8+ T cells by inhibiting thecircFOXP1/miR-4477a/PD-L1 signaling axis. Besides, Rg3 administration induced lipid oxidation and ROS reduction as detected by Flow cytometry, resulting in ferroptosis via theinactivation of circFOXP1/miR-4477a/PD-L1 axis. Ferroptosis inhibitor Fer-1 administration could reverse the beneficial effects caused by Rg3 treatment while ferroptosis inducer Erastin treatment enhanced the effects. Moreover, Rg3 gavage alleviated tumor growth and elevated ferroptosis and apoptosis in tumor tissues, which were prevented by PD-L1 overexpression. Furthermore, Rg3 was demonstrated to activate the function of CD8+ T cells via regulating thecircFOXP1-miR-4477a-PD-L1 signaling axis in vivo. Rg3 inactivated thecircFOXP1-miR-4477a-PD-L1 signaling axis to activate the immune function of CD8+ T cells, thereby inducing ferroptosis and apoptosis in GBC cells. This research recognizes the mechanism of Rg3-mediated anti-cancer effect and offers evidence for the potentiality of Rg3 in clinical application for GBC therapy.