YAP1 Axis Research Articles

LncRNA NUTM2A-AS1 silencing inhibits glioma via miR-376a-3p/YAP1 axis

The lncRNA NUTM2A-AS1 has been shown to be dysregulated in gastric cancer, while the roles in glioma is unclear. The aim of this study was to investigate the roles and potential mechanisms of lncRNA NUTM2A-AS1 in the proliferation and apoptosis of glioma cells. The StarBase software and dual luciferase reporter assay were used to identify the relationship between lncRNA NUTM2A-AS1 and miR-376a-3p, and miR-376a-3p and YAP1. The expression of lncRNA NUTM2A-AS1, miR-376a-3p, and YAP1 in human glioma cell lines was detected by qRT-PCR. MTT and flow cytometry were used to detect the effects of lncRNA NUTM2A-AS1 or miR-376a-3p on the proliferation and apoptosis of U251 and A172 cells, respectively. In addition, changes of Bax and Bcl-2 expression in glioma cells were further verified by western blotting and qRT-PCR. The results showed that the expression of lncRNA NUTM2A-AS1 was elevated in glioma cell lines, while miR-376a-3p was decreased. LncRNA NUTM2A-AS1 was negatively correlated with miR-376a-3p. Silencing of lncRNA NUTM2A-AS1 enhanced the levels of miR-376a-3p, leading to reduced cell proliferation and increased apoptosis in glioma cells. YAP1 was a direct target of miR-376a-3p, and it was negatively regulated by miR-376a-3p in U251 and A172 cells. Further mechanistic studies suggested that miR-376a-3p reduced glioma cell proliferation and increased apoptosis by inhibiting YAP1 expression. In addition, lncRNA NUTM2A-AS1 positively regulated of YAP1 expression in glioma cells. In conclusion, silencing of lncRNA NUTM2A-AS1 inhibited proliferation and induced apoptosis in human glioma cells via the miR-376a-3p/YAP1 axis.

Circ_0091579 Knockdown Inhibited HCC Proliferation and Glutamine Metabolism Through miR-1270/YAP1 Axis.

A growing number of studies have indicated that circRNAs play an important role in the progression of malignant tumors, including hepatocellular carcinoma (HCC). In this study, we designed to explore the abnormal expression of hsa_circ_0091579 (circ_0091579) and its role in the pathogenesis of HCC. In this study, the mRNA levels of circ_0091579, miR-1270, and Yes-associated protein (YAP1) were assessed by quantitative real-time polymerase chain reaction (qRT-PCR). RNase R and Actinomycin D were used to test the stability of circ_0091579. Cell Counting Kit-8 (CCK-8) was used to measure cell viability. Tubule formation assay was used to determine the effect of HCC cells on the number of tubes. Cell apoptosis was detected by flow cytometry. Western blot was used for the protein levels. Transwell and wound healing tests were used to measure the abilities of invasion and migration. The effect of circ_0091579 knockdown on tumor growth was verified in vivo by xenograft tumor assay and Immunohistochemistry (IHC) analysis. Dual-luciferase reporter or RIP assay was used to detect the relationship between miR-1270 and circ_0091579 or YAP1. Glutamine metabolism was determined by ELISA and western blot assays. In the present study, we found that circ_0091579 was upregulated in HCC tissues and cells. Inhibited circ_0091579 expression significantly suppressed proliferation and promoted apoptosis of HCC cells. Moreover, circ_0091579 knockdown inhibited tumor growth in vivo. Bioinformatic prediction and luciferase assay showed that circ_0091579 acted as a molecular sponge for miR-1270 and YAP1 was a target gene of miR-1270. MiR-1270 silencing could reverse the inhibitory effect of circ_0091579 knockdown on HCC progression, and YAP1 overexpression also could reverse the suppressive effect of circ_0091579 silencing on HCC progression. Meanwhile, miR-1270 inhibitor could invert the negative regulation effect of circ_0091579 silencing on YAP1 expression. Circ_0091579 promoted HCC progression by regulating the miR-1270/YAP1 axis, and our study might offer novel biomarkers and therapeutic targets for HCC.

Extracellular Vesicles Derived circSH3PXD2A Inhibits Chemoresistance of Small Cell Lung Cancer by miR-375-3p/YAP1.

Small cell lung cancer (SCLC) is a subtype of lung cancer with high malignancy and poor prognosis. Rapid acquisition of chemoresistance is one of the main reasons leading to clinical treatment failure of SCLC. Studies have indicated that circRNAs participate in multiple processes of tumor progression, including chemoresistance. However, the molecular mechanisms of circRNAs driving the chemoresistance of SCLC are not well specified. The differentially expressed circRNAs were screened by transcriptome sequencing of chemoresistant and chemosensitive SCLC cells. The EVs of SCLC cells were isolated and identified by ultracentrifugation, Western blotting, transmission electron microscopy, nanoparticle tracking analysis and EVs uptake assays. The expression levels of circSH3PXD2A in serum and EVs of SCLC patients and healthy individuals were detected by qRT‒PCR. The characteristics of circSH3PXD2A were detected by Sanger sequencing, RNase R assay, nuclear-cytoplasmic fraction assay, and fluorescence in situ hybridization assay. The mechanisms of circSH3PXD2A inhibiting SCLC progression were studied by bioinformatics analysis, chemoresistance assay, proliferation assay, apoptosis assay, transwell assay, pull-down assay, luciferase reporting assay, and mouse xenograft assay. It was identified that the circSH3PXD2A was a prominently downregulated circRNA in chemoresistant SCLC cells. The expression level of circSH3PXD2A in EVs of SCLC patients was negatively associated with chemoresistance, and the combination of EVs-derived circSH3PXD2A and serum ProGRP (Progastrin-releasing peptide) levels had better indications for DDP-resistant SCLC patients. CircSH3PXD2A inhibited the chemoresistance, proliferation, migration, and invasion of SCLC cells through miR-375-3p/YAP1 axis in vivo and in vitro. SCLC cells cocultured with EVs secreted by circSH3PXD2A-overexpressing cells exhibited decreased chemoresistance and cell proliferation. Our results manifest that EVs-derived circSH3PXD2A inhibits the chemoresistance of SCLC through miR-375-3p/YAP1 axis. Moreover, EVs-derived circSH3PXD2A may serve as a predictive biomarker for DDP-resistant SCLC patients.

E2F1-mediated ectopic expression of PP1A promotes breast cancer progression via activation of YAP1.

Hormone receptor-positive breast cancer is the most common subtype of breast cancer. The protein phosphatase PP1A gene is described as an oncogene in several tumor types; however, the biological function of PP1A in hormone receptor-positive breast cancer remains unclear. The Cancer Genome Atlas data indicates PP1A expression is upregulated in hormone receptor-positive breast cancer tissues than in normal breast tissues. We explored the biological function of PP1A in hormone receptor-positive breast cancer using MTT assays, colony formation assays, and a xenograft mouse model. The results indicated that PP1A promoted hormone receptor-positive breast cancer proliferation, both in vitro and in vivo. Mechanistically, LINC02754 recruited the binding of the transcription factor E2F1 to the PP1A promotor, thereby increasing PP1A expression. The PP1A then interacted with and dephosphorylated YAP1, resulting in YAP1 activation. The dephosphorylated YAP1 moved to the nucleus and increased the expression of the downstream oncogene CTGF, promoting hormone receptor-positive breast cancer progression. Our findings reveal the function of the LINC02754/E2F1/PP1A/YAP1 axis in hormone receptor-positive breast cancer and provide new insight into hormone receptor-positive breast cancer progression.

PVT1 inhibition stimulates anti-tumor immunity, prevents metastasis, and depletes cancer stem cells in squamous cell carcinoma

Cancer stem cells (CSCs) cause tumor metastasis and immune evasion by as-yet-unknown molecular mechanisms. In the present study, we identify a long noncoding RNA (lncRNA), termed PVT1, which is highly expressed in CSCs and correlated closely with lymph node metastasis of head and neck squamous cell carcinoma (HNSCC). PVT1 inhibition eliminates CSCs, prevents metastasis, and stimulates anti-tumor immunity, while inhibiting HNSCC growth. Moreover, PVT1 inhibition promotes the infiltration of CD8+ T cells into the tumor microenvironment, thereby enhancing immunotherapy by PD1 blockade. Mechanistically, PVT1 inhibition stimulates the DNA damage response, which induces CD8+ T cell-recruiting chemokines, while preventing CSCs and metastasis via regulating the miR-375/YAP1 axis. In conclusion, targeting PVT1 might potentiate the elimination of CSCs via immune checkpoint blockade, prevent metastasis, and inhibit HNSCC growth.

LncRNA MSC-AS1, as an oncogene in melanoma, promotes the proliferation and glutaminolysis by regulating the miR-330-3p/ YAP1 axis.

Melanoma is a kind of aggressive skin neoplasms with high mortality. The purpose of this present research was to investigate the effects and potential mechanisms of long-noncoding RNA (lncRNA) MSC antisense RNA 1 (MSC-AS1) in melanoma. MSC-AS1, miR-330-3p and YAP1 expression levels in melanoma tissues and cells were assessed by quantitative real-time polymerase chain reaction. Melanoma cells were evaluated using cell count kit-8, clone formation and ELISA in vitro . The relationship among MSC-AS1, YAP1 and miR-330-3p was validated by pull-down and luciferase reporter assays. Finally, the role of MSC-AS1 in vivo was determined by the xenograft model. Results showed that lncRNA MSC-AS1 was upregulated in melanoma tissues and cells. High expression of MAS-AS1 was positively correlated with a poor prognosis. Pull-down and luciferase reporter demonstrated that miR-330-3p specifically binds directly to YAP1 and MSC-AS1, respectively. MSC-AS1 promoted the expression of YAP1 by downregulating miR-330-3p. Functional experiments suggested that knockdown of MSC-AS1 suppressed the proliferation of melanoma cells and decreased the levels of glutamine, glutamate and α-ketoglutarate, glutaminase and glutamine transporter alanine-serine-cysteine transporter 2. Upregulation of miR-330-3p alleviated the promotion effect of MSC-AS1 overexpression on the proliferation and glutaminolysis of melanoma cells. The above changes could be reversed by YAP1 overexpression. In addition, knockdown of MSC-AS1 dramatically restrained the growth of melanoma cells in xenograft model. In conclusion, our results revealed that MSC-AS1 facilitated the proliferation and glutaminolysis of melanoma cells by regulating miR-330-3p/ YAP1 pathway, suggesting that MSC-AS1 could provide a new idea for the treatment of melanoma.

Withdrawn: L. Ma, T. Li, G. Liu, J. Wang, Z. Yin, J. Kang, LncRNA RHPN1-AS1 modulates cholangiocarcinoma progression and is related with poor clinical outcomes through miR-345-5p/YAP1 axis.

Withdrawal: L. Ma, T. Li, G. Liu, J. Wang, Z. Yin, J. Kang, LncRNA RHPN1-AS1 modulates cholangiocarcinoma progression and is related with poor clinical outcomes through miR-345-5p/YAP1 axis, J. Gastroenterol. Hepatol. 2021, (https://onlinelibrary.wiley.com/doi/epdf/10.1111/jgh.15374). The above article, published online on December 16, 2020 in Wiley Online Library (wileyonlinelibrary.com), has been withdrawn by agreement between the journal Editor-in-Chief Prof. Joseph Sung, and John Wiley & Sons, Ltd. The Withdrawal has been agreed because the final article was not approved for publication by the authors.

Circular RNA LONP2 regulates proliferation, invasion, and apoptosis of bladder cancer cells by sponging microRNA-584-5p

ABSTRACT Bladder cancer (BC) is the most frequent type of urinary tumor and a barely treatable disease. Although extensive efforts have been invested in the research of BC, the underlying etiology and pathophysiology remain unclear. CircLONP2 is a circular RNA implicated in the development of many cancers, and miR-584-5p and YAP1 have been reported to contribute to the progression of BC. In this research, we presented novel evidence supporting circLONP2/miR-584-5p/YAP1 axis as a novel regulatory module in the progression of BC. We analyzed the expression of circLONP2 between precancerous BC samples and normal tissues using a published RNA-seq dataset. The expression of circLONP2 was also validated in clinical samples and cell lines by quantitative RT-PCR. Small interfering RNA (siRNA) and miRNA inhibitor was utilized to modulate the expression of circLONP2 and miR-584-5p and investigate their functions on cell proliferation and invasion. Luciferase reporter assay and RNA pull-down were performed to confirm the functional interactions among circLONP2/miR-584-5p/YAP1. CircLONP2 was significantly upregulated in precancerous BC tissues and BC cells. CircLONP2 depletion inhibited cell viability, proliferation, and invasion of BC cell lines, which could be partially rescued by miR-584-5p inhibitor. Further experiments indicated that miR-584-5p regulates cell viability, proliferation, and invasion via directly targeting YAP1. In summary, our work indicates that circLONP2 plays an oncogenic function in BC by regulating miR-584-5p/YAP1 axis, and its interaction with miR-584-5p provides a potential strategy to target BC.

Quercetin attenuates the proliferation, inflammation, and oxidative stress of high glucose-induced human mesangial cells by regulating the miR-485-5p/YAP1 pathway.

BackgroundDiabetic nephropathy (DN) is a kidney damage caused by diabetes and the main cause of end-stage renal disease. However, the current treatment of DN has many limitations. Quercetin is a bioflavonoid compound with therapeutic benefits in metabolic diseases. This study aims to determine the therapeutic potentials and underlying mechanism of quercetin on DN.MethodsWe collected blood samples from DN patients and healthy controls and treated human mesangial cells (HMCs) with high glucose (HG) to establish an in vitro model of DN. Then we assessed the expression difference of miR-485-5p as well as YAP1 in serum of DN patients and healthy controls and between HG-induced HMCs and control cells. qRT-PCR and western blot were performed to assess miR-485-5p and YAP1 expression levels; CCK-8 and ELISAs were used to examine cell proliferation, inflammation, and oxidative stress. Dual luciferase reporter assay was implemented to detect the binding of miR-485-5p and YAP1 mRNA sequence.ResultsQuercetin suppressed proliferation, inflammation, and oxidative stress of HMCs induced by HG. As for mechanism, miR-485-5p directly bound to YAP1 and inhibited YAP1 expression. The downregulation of miR-485-5p and upregulation of YAP1 were also observed in the serum of DN patients. Quercetin modulated miR-485-5p/YAP1 axis to regulate HG-induced inflammation and oxidative stress.Conclusion:Quercetin inhibits the proliferation, inflammation, and oxidative stress of HMCs induced by HG through miR-485-5p/YAP1 axis, which might provide a novel treatment strategy for DN.

LncRNA ASAP1-IT1 enhances cancer cell stemness via regulating miR-509-3p/YAP1 axis in NSCLC

BackgroundNon-small cell lung cancer (NSCLC) is a major cause of cancer-related death worldwide, and cancer stem cell is responsible for the poor clinical outcome of NSCLC. Previous reports indicated that long noncoding RNAs (lncRNAs) play important roles in maintaining cancer stemness, however, the underlying mechanisms remain unclear. This study investigates the role of ASAP1 Intronic Transcript 1 (ASAP1-IT1) in cancer cell stemness of NSCLC.MethodsThe expression of ASAP1-IT1, microRNA-509-3p (miR-509-3p) and apoptosis-/stemness-related genes was analyzed by qRT-PCR in NSCLC tissues, cancer cells and spheres of cancer stem cells. Knockdown of ASAP1-IT1 or overexpression of miR-509-3p in NSCLC cells by infection or transfection of respective plasmids. Sphere formation and colony formation were used to detect NSCLC stem cell-like properties and tumor growth in vitro. Luciferase reporter assays, RNA immunoprecitation (RIP) and qRT-PCR assays were used to analyze the interaction between lncRNA and miRNA. The expression of expression of regulated genes of ASAP1-IT1/miR-509-3p axis was evaluated by qRT-PCR and Western blot. The NSCLC xenograft mouse model was used to validate the role of ASAP1-IT1 in NSCLC stemness and tumor growth in vivo.ResultsASAP1-IT1 was up-regulated in NSCLC tissues, cancer cells, and in spheres of A549-derived cancer stem cells. Downregulation of ASAP1-IT1 or overexpression of miR-509-3p significantly decreased cell colony formation and stem cell-like properties of A549-dereived stem cells with decreased expression of stem cell biomarkers SOX2, CD34, and CD133, and suppressing the expression of cell growth-related genes, Cyclin A1, Cyclin B1, and PCNA. Furthermore, knockdown of ASAP1-IT1 or overexpression of miR-509-3p repressed tumor growth in nude mice via reducing expression of tumorigenic genes. ASAP1-IT1 was found to interact with miR-509-3p. Moreover, overexpression of ASAP1-IT1 blocked the inhibition by miR-509-3p on stem cell-like properties and cell growth of A549-dereived stem cells both in vitro and in vivo. Finally, the level of YAP1 was regulated by ASAP1-IT1 and miR-509-3p.ConclusionsYAP1-involved ASAP1-IT1/miR-509-3p axis promoted NSCLC progression by regulating cancer cell stemness, and targeting this signaling pathway could be is a promising therapeutic strategy to overcome NSCLC stemness.

CircPTK2 (hsa_circ_0003221) Contributes to Laryngeal Squamous Cell Carcinoma by the miR-1278/YAP1 Axis.

Laryngeal cancer accounts for 20% of all head and neck malignancies. Laryngeal squamous cell carcinoma (LSCC) is the most common type of laryngeal cancer and is characterized by squamous differentiation, a high mortality rate, and poor prognosis. Accumulating studies have indicated that circular RNAs (circRNAs) are critical regulators in many cancers. CircPTK2 exerts an important regulatory role in several cancers. In this study, we aimed to elucidate the function of circPTK2 (hsa_circ_0003221) in LSCC. Through a series of investigations, we discovered that circPTK2 was significantly upregulated in LSCC tissues cells. Functionally, cell counting kit-8 (CCK-8) and flow cytometry analyses revealed that knockdown of circPTK2 suppressed LSCC cell viability and the cell cycle while promoting cell apoptosis. Notably, silencing circPTK2 inhibited tumor growth in vivo. Mechanistically, circPTK2 functioned as a molecular sponge of miR-1278 to upregulate YAP1 expression in LSCC cells. Moreover, YAP1 knockdown inhibited malignant phenotypes of LSCC cells. The rescue experiments showed that YAP1 overexpression reversed the effects of circPTK2 on LSCC cells. Therefore, we concluded that circPTK2 facilitates LSCC progression through the miR-1278/YAP1 axis.

A SOX-9-NAV3-YAP1 axis in kidney fibrosis.

A SOX-9-NAV3-YAP1 axis in kidney fibrosis.

MiR-21-3p Promotes Hepatocellular Carcinoma Progression via SMAD7/YAP1 Regulation.

BackgroundHepatocellular carcinoma (HCC) remains a major global health burden due to its high prevalence and mortality. Emerging evidence reveals that microRNA (miRNA) plays a vital role in cancer pathogenesis and is widely involved in the regulation of signaling pathways via their targeting of downstream genes. MiR-21-3p, a liver-enriched miRNA, and SMAD7, the negative regulator of the TGF-β signaling pathway, likely exert a vital influence on HCC progression.AimsHere, we explore the role of the miR-21-3p-SMAD7/YAP1 axis on HCC pathogenesis.MethodsMiRNA microarray analysis was performed for miRNA screening. The dual-luciferase assay was adopted for target verification. Expression of miRNA and related genes were quantified via qRT-PCR, western blotting, and immunohistochemical staining. Flow cytometry and the transwell migration assay were used to detail cell apoptosis, invasion and metastases. Rat models were established to explore the role of the miR-21-3p-SMAD7/YAP1 axis in hepatocarcinogenesis. Bioinformatics analysis was conducted for exploring genes of clinical significance.ResultsMiR-21-3p levels were found to be significantly elevated in hepatocellular carcinoma and indicate poor overall survival. High miR-21-3p levels were associated with advanced tumor stages (P = 0.029), in particular T staging (P = 0.026). Low SMAD7/high YAP1 levels were confirmed in both HCC and rat models with advanced liver fibrosis and cirrhosis. Besides, SMAD7 was demonstrated to be the direct target of miR-21-3p. The effect of MiR-21-3p on tumor phenotypes and YAP1 upregulation could be partly reversed via the restoration of SMAD7 expression in HCC cell lines. Overexpression of YAP1 after miR-21-3p upregulation promoted expression of nuclear transcription effector connective tissue growth factor. Co-survival analysis indicated that lower miR-21-3p/higher SMAD7 (P = 0.0494) and lower miR-21-3p/lower YAP1 (P = 0.0379) group patients had better overall survival rates. Gene Set Variation Analysis revealed that gene sets related to miR-21-3p and SMAD7 were significantly associated with the TGF-β signaling pathway in HCC.ConclusionMiR-21-3p promotes migration and invasion of HCC cells and upregulation of YAP1 expression via direct inhibition of SMAD7, underscoring a major epigenetic mechanism in the pathogenesis of HCC.

Hsa_circ_0005273 facilitates breast cancer tumorigenesis by regulating YAP1-hippo signaling pathway

BackgroundCircular RNAs (circRNAs), a novel class of endogenous RNAs, have shown to participate in the development of breast cancer (BC). Hsa_circ_0005273 is a circRNA generated from several exons of PTK2. However, the potential functional role of hsa_circ_0005273 in BC remains largely unknown. Here we aim to evaluate the role of hsa_circ_0005273 in BC.MethodsThe expression level of hsa_circ_0005273 and miR-200a-3p were examined by RT-qPCR in BC tissues and cell lines. The effect of knocking down hsa_circ_0005273 in BC cell lines were evaluated by examinations of cell proliferation, migration and cell cycle. In addition, xenografts experiment in nude mice were performed to evaluate the effect of hsa_circ_0005273 in BC. RNA immunoprecipitation assay, RNA probe pull-down assay, luciferase reporter assay and fluorescence in situ hybridization were conducted to confirm the relationship between hsa_circ_0005273, miR-200a-3p and YAP1.ResultsHsa_circ_0005273 is over-expressed in BC tissues and cell lines, whereas miR-200a-3p expression is repressed. Depletion of hsa_circ_0005273 inhibited the progression of BC cells in vitro and in vivo, while overexpression of hsa_circ_0005273 exhibited the opposite effect. Importantly, hsa_circ_0005273 upregulated YAP1 expression and inactivated Hippo pathway via sponging miR-200a-3p to promote BC progression.ConclusionsHsa_circ_0005273 regulates the miR-200a-3p/YAP1 axis and inactivates Hippo signaling pathway to promote BC progression, which may become a potential biomarker and therapeutic target.

NUSAP1 Promotes Gastric Cancer Tumorigenesis and Progression by Stabilizing the YAP1 Protein.

The Yes-associated protein (YAP1) is a main effector of the canonical Hippo pathway, which contributes greatly to tumor initiation, progression, and metastasis in multiple cancers, including gastric cancer (GC). Due to limited knowledge of YAP1 upregulation in cancer, it is a great challenge of therapeutic targets toward the Hippo–YAP1 pathway. Here, we identify nucleolar spindle-associated protein 1 (NUSAP1) as a novel binding partner of YAP1. The upregulation of NUSAP1 is associated with unfavorable clinical outcomes in GC patients, and NUSAP1 depletion impairs its oncogenic properties in vitro and in a xenograft model. Mechanistically, we discovered that NUSAP1 functions as a positive regulator of YAP1 protein stability, thereby inducing the transcription of Hippo pathway downstream target genes, such as CTGF and CYR61. More interestingly, we find that the cancer-promoting effects of NUSAP1 on GC cell growth, migration, and invasion are mainly mediated by YAP1. Furthermore, aberrant expression of NUSAP1 and YAP1 is highly correlated in GC cell lines and tissues. We herein clarify the role of the oncogenic NUSAP1–YAP1 axis in GC tumorigenesis and progression and, therefore, provide novel therapeutic targets for GC treatment.

Linc00475 promotes the progression of glioma by regulating the miR-141-3p/YAP1 axis.

Glioma is the most prevalent and lethal primary brain tumour. Abundant long non‐coding RNAs ( lncRNAs) are aberrant and play crucial roles in the oncogenesis of glioma. The exact functions of linc00475 in glioma remain blurred. Here, we analysed the expression levels of linc00475 by qRT‐PCR and discovered that linc00475 was up‐regulated in glioma and predicted a poor prognosis in patients with glioma. Besides, inhibiting linc00475 restrained the progression of glioma in vitro and in vivo. Further experiments confirmed that linc00475 regulated the progression of glioma by acting as a sponge for miR‐141‐3p. Moreover, we detected the binding sites of linc00475 and miR‐141‐3p, the YAP1‐ 3′UTR and miR‐141‐3p by luciferase reporters. The rescue assays confirmed that inhibiting linc00475 restrained the progression of glioma through the miR‐141‐3p/YAP1 pathway. Collectively, our research demonstrates the key roles of linc00475 in glioma, which could be a promising therapeutic target.

Dlk1 regulates quiescence in calcitonin receptor-mutant muscle stem cells.

Muscle stem cells, also called muscle satellite cells (MuSCs), are responsible for skeletal muscle regeneration and are sustained in an undifferentiated and quiescent state under steady conditions. The calcitonin receptor (CalcR)-protein kinase A (PKA)-Yes-associated protein 1 (Yap1) axis is one pathway that maintains quiescence in MuSCs. Although CalcR signaling in MuSCs has been identified, the critical CalcR signaling targets are incompletely understood. Here, we show the relevance between the ectopic expression of delta-like non-canonical Notch ligand 1 (Dlk1) and the impaired quiescent state in CalcR-conditional knockout (cKO) MuSCs. Dlk1 expression was rarely detected in both quiescent and proliferating MuSCs in control mice, whereas Dlk1 expression was remarkably increased in CalcR-cKO MuSCs at both the mRNA and protein levels. It is noteworthy that all Ki67+ non-quiescent CalcR-cKO MuSCs express Dlk1, and non-quiescent CalcR-cKO MuSCs are enriched in the Dlk1+ fraction by cell sorting. Using mutant mice, we demonstrated that PKA-activation or Yap1-depletion suppressed Dlk1 expression in CalcR-cKO MuSCs, which suggests that the CalcR-PKA-Yap1 axis inhibits the expression of Dlk1 in quiescent MuSCs. Moreover, the loss of Dlk1 rescued the quiescent state in CalcR-cKO MuSCs, which indicates that the ectopic expression of Dlk1 disturbs quiescence in CalcR-cKO. Collectively, our results suggest that ectopically expressed Dlk1 is responsible for the impaired quiescence in CalcR-cKO MuSCs.

NEK1 Phosphorylation of YAP Promotes Its Stabilization and Transcriptional Output.

Simple SummaryWe earlier described the involvement of the TLK1>NEK1>ATR>Chk1 axis as a key determinant of cell cycle arrest in androgen-dependent prostate cancer (PCa) cells after androgen deprivation. We now report that the TLK1>NEK1 axis is also involved in stabilization of yes-associated protein 1 (YAP1), the transcriptional co-activator in the Hippo pathway, presumably facilitating reprogramming of the cells toward castration-resistant PCa (CRPC). NEK1 interacts with YAP1 physically resulting in its phosphorylation of 6 residues, which enhance its stability and activity. Analyses of cancer Protein Atlas and TCGA expression panels revealed a link between activated NEK1 and YAP1 expression and several YAP transcription targets.Most prostate cancer (PCa) deaths result from progressive failure in standard androgen deprivation therapy (ADT), leading to metastatic castration-resistant PCa (mCRPC); however, the mechanism and key players leading to this are not fully understood. While studying the role of tousled-like kinase 1 (TLK1) and never in mitosis gene A (NIMA)-related kinase 1 (NEK1) in a DNA damage response (DDR)-mediated cell cycle arrest in LNCaP cells treated with bicalutamide, we uncovered that overexpression of wt-NEK1 resulted in a rapid conversion to androgen-independent (AI) growth, analogous to what has been observed when YAP1 is overexpressed. We now report that overexpression of wt-NEK1 results in accumulation of YAP1, suggesting the existence of a TLK1>NEK1>YAP1 axis that leads to adaptation to AI growth. Further, YAP1 is co-immunoprecipitated with NEK1. Importantly, NEK1 was able to phosphorylate YAP1 on six residues in vitro, which we believe are important for stabilization of the protein, possibly by increasing its interaction with transcriptional partners. In fact, knockout (KO) of NEK1 in NT1 PCa cells resulted in a parallel decrease of YAP1 level and reduced expression of typical YAP-regulated target genes. In terms of cancer potential implications, the expression of NEK1 and YAP1 proteins was found to be increased and correlated in several cancers. These include PCa stages according to Gleason score, head and neck squamous cell carcinoma, and glioblastoma, suggesting that this co-regulation is imparted by increased YAP1 stability when NEK1 is overexpressed or activated by TLK1, and not through transcriptional co-expression. We propose that the TLK1>NEK1>YAP1 axis is a key determinant for cancer progression, particularly during the process of androgen-sensitive to -independent conversion during progression to mCRPC.

The DLG1-AS1/miR-497/YAP1 axis regulates papillary thyroid cancer progression.

The long non-coding RNA (lncRNA), DLG1-AS1, is upregulated in papillary thyroid cancer (PTC) tissues and cell lines. Here, we found that increased expression of DLG1-AS1 caused lymph node metastasis and advanced tumor-node-metastasis (TNM) stage. DLG1-AS1 knockdown inhibited proliferation, invasion, and migration of PTC cells, and impaired tumorigenesis in vivo in mouse xenografts. DLG1-AS1 functions as a competing endogenous RNA (ceRNA) for miR-497. Further investigation revealed that DLG1-AS1 regulated yes-associated protein 1 (YAP1; a known target of miR-497) by competitively binding to miR-497. Moreover, inhibition of miR-497 abrogated the inhibitory effects of DLG1-AS1 depletion on PTC cells. These findings demonstrate that the DLG1-AS1–miR-497–YAP1 axis promotes the growth and metastasis of PTC by forming a ceRNA network.

MiR-582-3p alleviates osteoarthritis progression by targeting YAP1

Osteoarthritis (OA) is a widespread degenerative joint disease that affects more than 350 million people worldwide. Although YAP1 has been proved to play a key role in OA, the biological function and mechanism of YAP1 in OA still need further investigation. In the present study, we demonstrated that YAP1 was highly expressed in OA rat chondrocytes. Recently, growing microRNAs (miRNAs) have been reported to play important roles in OA development. Among them, miR-582-3p is one of the few significantly downregulated miRNAs and attracted our attention. Functional investigations indicated that miR-582-3p inhibited chondrocyte apoptosis, reduced the proinflammatory cytokine production and suppressed extracellular matrix (ECM) degradation. Subsequently, molecular mechanism exploration implied that YAP1 is a downstream target of miR-582-3p. Furthermore, rescue assays revealed that YAP1 amplification can reverse miR-582-3p mimic-mediated effects on chondrocyte apoptosis, inflammatory response, and ECM degradation. Moreover, the OA rat model was established to explore the function of miR-582-3p/YAP1 axis in vivo. The results showed that YAP1 overexpression can recover the effects induced by injection of AAV-miR-582-3p mimic on OA progression. To sum up, these findings implied a crucial role of miR-582-3p/YAP1 axis in OA, which may provide a promising therapeutic strategy for OA.